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THE UPPERMOST LOWER EOCENE BLUE RIM FLORA FROM THE BRIDGER FORMATION OF SOUTHWESTERN WYOMING: FLORISTIC COMPOSITION, PALEOCLIMATE, AND PALEOECOLOGY

SARAH ELIZABETH ALLEN

A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA

2017

To my parents

ACKNOWLEDGMENTS

Thank you to my advisor, Steven R. Manchester, for his guidance, support, and valuable comments. My committee members, Ellen Martin, Walter Judd, and Jonathan Bloch are gratefully acknowledged. Hongshan Wang spent hours curating Blue Rim fossils at the FLMNH and always provided a welcoming space to work in the collections. Paleobotany lab manager,

Terry Lott, is acknowledged for his help with specimens and around the lab. Thank you also to the other members of the paleobotany lab: Greg Stull, Fabiany Herrera, Paula Mejia-Velasquez,

Nareerat Boonchai, Jui Hui, Rebecca Koll, Fani Plascencia, Xiaoyan Liu, Yuling Na, Nathan

Jud, Chris Nelson, Bob Spielbauer, Nazi Balmaki, Han Meng, and Li Long.

Thank you to those who helped with fieldwork at Blue Rim in 2010, 2012. and 2014: Jim

Barkley, Nareerat Boonchai, Sahale Casebolt, Ellen Currano, Don and Kathy Hopkins, Jui Hui,

Grant Godden, Xiaoyan Liu, Terry Lott, Steve Manchester, Keith McCall, Paul Murphey, Mike

Smith, and Greg Stull. I must add additional thanks to Steve for allowing me to use his van for fieldwork and to Sahale and Terry for help in driving between Wyoming and Florida in the summer of 2014. Scott Wing let me join him in the Bighorn Basin for some additional fieldwork experience in the summer of 2011.

Additional fossil specimens studied were collected and donated to the FLMNH by Jane

Landeen (who discovered the Blue Rim site), Jim Barkley, and Howard and Darlene Emry.

Bruce Handley collected and donated material from Watson, UT to the UCMP at Berkeley.

Work on this project was assisted by discussions with William Bartels, Nareerat

Boonchai, Laura Calvillo-Canadell, Sergio Cevallos-Ferriz, Peter Crane, John Dransfield,

Emmett Evanoff, Carol Furness, Gregg Gunnell, Madeline Harley, Christa Hofmann, David

Jarzen, Nathan Jud, Chris Nelson, Kristen Porter-Utley, Bill Rember, Paula Rudall, Bandana

Samant, Selena Smith, Rashmi Srivastava, Elisabeth Wheeler, Scott Wing, and John-Paul

Zonneveld. More extensive research collaborations with Steve Manchester, Greg Stull,

Mac Alford, and Mike Smith are also appreciated.

Many of the photos of macrofossils were taken by student workers and volunteers including: Catherine Snyder, Morgan Kerr, Ariel Guggino, Xiaojuan Zhou, and Megan Kean.

Student research volunteers also documented and photographed macrofossils and many of the dispersed pollen slides. Thank you to William Paxton, Alyssa Zakala, Jonathan Wilson, and a special thanks and appreciation to Morgan Pinkerton for all of her hard work and research.

Scott Wing, Kirk Johnson, and Diane Erwin provided access to fossil specimens studied at the USNM, the DMNS, and UCMP, respectively. M. E. Collinson provided comparative data on related fossils from the London Clay flora (Chapter 5). I also thank the herbarium staff at the

FLMNH, Wageningen, Leiden, Kim Kersh at the University and Jepson Herbaria (UC Berkeley), and J. Solomon at the Missouri Botanical Garden for facilitating study of extant material.

My participation in an NSF funded short course on Plant Anatomy (microMORPH) at the

Arnold Arboretum of Harvard University in the summer of 2015 (instructors: Pieter Baas, Pam

Diggle, William (Ned) Friedman, Peter Gasson, Elisabeth Wheeler) greatly facilitated my knowledge of wood anatomy and allowed me to complete that aspect of my dissertation project.

Chris Nelson is acknowledged for preparing many of the recent wood slides.

Thank you to all my teaching supervisors and support staff: Kent Vliet, Jack Putz, Ann

Wagner, Stuart McDaniel, Norm Douglas, my fellow TA’s, and a special thanks to Christine

Davis for her support and for helping me improve my teaching as part of the Plant Anatomy course.

Research funding was provided by an NSF Doctoral Dissertation Improvement Grant

(DEB-1404895), the Evolving Earth Foundation, the Paleontological Society, and the UF

Department of Biology Mildren Mason Griffith Grant. Additional travel support was provided by

S.R. Manchester, the UF Dept. of Biology, UF Graduate Student Council. Thank you to the

Department of Biology for guaranteeing teaching support and to the UF College of Liberal Arts and Sciences Dissertation Fellowship which enabled me to complete my dissertation in my final semester.

Thank you also to UF Department of Biology and FLMNH financial staff members who helped to coordinate grant funds including: Shuronna Wilson, Ashley Gazich, Robb Stokes,

Darlene Novak, and Leila Long. I also thank Karen Patterson, Tangelyn Mitchell, and Susan

Spaulding from the UF Department of Biology and the library and interlibrary loan staff at UF.

The FLMNH webmaster, Sarah Fazenbaker, provided assistance with setting up and facilitating my blog.

And finally, thank you to my friends and family for their continued support. My UF friends, including Emily Woodruff and Elizabeth Hamman, were always a sounding board and a source of fun. Deep appreciation is given to Jared Desrochers who sweated out many years in

Florida on my behalf and kept the fridge full when I did not have time to shop or cook. My parents took me on trips, let me fill up our suitcases with rocks, and encouraged my appreciation of the natural world. Their unwavering support was invaluable.

TABLE OF CONTENTS

page

ACKNOWLEDGMENTS ...... 4

LIST OF TABLES ...... 11

LIST OF FIGURES ...... 13

LIST OF ABBREVIATIONS ...... 21

ABSTRACT ...... 22

CHAPTER

1 GEOLOGICAL, PALEONTOLOGICAL AND PALEOCLIMATIC CONTEXT ...... 24

Part I: Regional Perspective ...... 24 Topographic and Geologic Setting ...... 24 Geology and Sedimentological Origins of the Bridger Formation ...... 31 Stratigraphic Members of the Bridger Formation ...... 33 The Bridgerian North American Land Mammal Age ...... 34 Radiometric Dating ...... 36 Early Paleontological Work in the Bridger Formation ...... 37 Fossil Fauna and Flora in the Bridger & Nearby Localities: 20th and 21st Centuries ...... 38 Regional Paleoenvironments and Paleoclimate Estimates ...... 43 Part II: Local Geology and Depositional Environment at Blue Rim ...... 46 Location of the Blue Rim Escarpment ...... 46 General Geologic Observations ...... 46 Geologic Field Observations about Specific Quarries ...... 48 Vertebrate Fossils at Blue Rim ...... 49 Invertebrate Fossils at Blue Rim ...... 50 Depositional Environment ...... 50 Radiometric Ages ...... 52 Part III: Dissertation Overview ...... 55 Overarching Research Questions ...... 55 Overview of the Following Chapters ...... 55

2 LEAF FOSSILS FROM BLUE RIM ...... 73

Part I: Leaves from the Isolated Channel Fill UF 19404 ...... 75 Toothed Laminae ...... 75 Entire-margined Laminae ...... 83 Summary of Isolated Channel Fill Leaves, Locality UF 19404 ...... 91 Part II: Dicotyledonous Leaf Morphotypes from the Lower Horizon ...... 92 Toothed Laminae ...... 92 Entire-margined Laminae ...... 114

Summary of Lower Horizon Leaves ...... 123 Part III: Leaf Morphotypes from the Upper Horizon ...... 124 Toothed Morphotypes ...... 125 Untoothed Morphotypes ...... 143 Monocot Foliage ...... 156 Non-Angiosperm Remains ...... 156 Summary of Upper Horizon Leaves ...... 157 Overall Discussion of Blue Rim Leaves ...... 158

3 REPRODUCTIVE STRUCTURES: MACROFOSSILS AND DISPERSED PALYNOFLORA ...... 244

Part I: Flowers and Inflorescences ...... 245 Overall discussion for Part I: Flowers ...... 264 Part II: Fruits and Seeds ...... 265 Non-Angiosperm Reproductive Structures ...... 279 Part III: Dispersed Pollen and Spores ...... 280 Material and Methods ...... 281 Systematics and Results ...... 282 Discussion ...... 285

4 FOSSIL PALM FLOWERS FROM THE EOCENE OF THE ROCKY MOUNTAIN REGION WITH AFFINITIES TO PHOENIX L. (ARECACEAE: CORYPHOIDEAE) ....331

Material, Methods, and Geologic Setting ...... 332 Material ...... 332 Methods ...... 333 Geologic Setting ...... 334 Systematics and Results ...... 335 Discussion ...... 337 Systematic Considerations ...... 338 Biogeography ...... 341 Fossil Record of Phoenix ...... 342 Paleoclimate Implications ...... 347 Conclusions...... 348

5 ICACINACEAE FROM THE EOCENE OF WESTERN NORTH AMERICA ...... 355

Materials and Methods ...... 358 Systematics and Results ...... 360 Discussion ...... 381 Overview of Icacinaceae Fossil Record ...... 381 Iodes Fossil Record ...... 383 Iodes Biogeography ...... 385 Systematic and Biogeographic Significance of Biceratocarpum ...... 386 Overview of Icacinicarya and Icacinicaryites ...... 387 Paleoecological Implications ...... 388

6 RECONSTRUCTING THE LOCAL VEGETATION AND SEASONALITY OF THE LOWER EOCENE BLUE RIM SITE OF SOUTHWESTERN WYOMING USING FOSSIL WOOD...... 405

Material and Methods ...... 405 Systematics and Results ...... 408 Gymnospermae ...... 408 Angiospermae ...... 411 Taphonomy and Size of Specimens ...... 438 Discussion ...... 441 Anatomy ...... 441 Density and Specific Gravity ...... 442 Vulnerability Index ...... 443 Ecology and Climate ...... 444 Comparison with Other Western Interior North American Eocene Wood Floras ...... 448 Comparison to Other Blue Rim Floral Elements ...... 450 Concluding Remarks ...... 452

7 FLORAL OVERVIEW, PALEOCLIMATE, AND PALEOECOLOGY OF BLUE RIM WITH A COMPARISION TO OTHER EARLY EOCENE SITES FROM WESTERN NORTH AMERICA ...... 471

Part I: Blue Rim Flora ...... 471 Part II: Paleoclimate and Paleoecology of Blue Rim ...... 473 UF 19404: Isolated Channel Fill ...... 481 Lower Horizon ...... 482 Upper Horizon ...... 486 Discussion of Paleoclimate Results ...... 487 Part III: Comparison to Other Early Eocene Floras ...... 489 Part IV: Summary and Conclusions ...... 498

APPENDIX

A SUPPLEMENTAL DATA FOR CHAPTER 1 ...... 514

B INDIVIDUAL LEAF SPECIMEN DESCRIPTIONS...... 526

Part I: UF Locality 19404 ...... 526 Part II: Dicotyledonous Leaf Morphotypes from the Lower Horizon ...... 533 Part III: Dicotyledonous Leaf Morphotypes from the Upper Horizon ...... 546

C INDIVIDUAL REPRODUCTIVE SPECIMEN DESCRIPTIONS ...... 565

D INDIVIDUAL WOOD SPECIMEN DESCRIPTIONS ...... 570

E CLAMP SCORE SHEET ...... 580

LIST OF REFERENCES ...... 582

BIOGRAPHICAL SKETCH ...... 618

LIST OF TABLES

Table page

1-1. Summary of single crystal sanidine 40Ar/39Ar analyses: Bridger Formation, Blue Rim, WY...... 60

2-1. Morphotypes present in more than one leaf horizon ...... 160

3-1. Summary of reproductive structures at Blue Rim...... 292

5-1. List of herbarium specimens examined for fruit comparative work...... 391

5-2. List of herbarium specimens examined for leaf comparative work ...... 392

6-1. Comparison of the Blue Rim (Bridger Formation, WY) and Clarno Formation (OR, Wheeler and Manchester, 2002) legumes...... 454

6-2. Equations used to estimate tree height from diameter...... 455

6-3. Estimated tree heights of ten Blue Rim fossil wood specimens calculated from the diameter...... 456

7-1. Mean annual temperature (MAT) estimates using leaf margin analysis (LMA) for the UF 19404 site at Blue Rim...... 504

7-2. Mean annual precipitation (MAP) estimates using leaf area analysis (LAA) for the UF 19404 site at Blue Rim...... 505

7-3. Mean annual temperature (MAT) estimates using leaf margin analysis for the lower horizon quarries at Blue Rim...... 506

7-4. Mean annual precipitation (MAP) estimates using leaf area analysis (LAA) for the lower horizon quarries at Blue Rim...... 507

7-5. CLAMP results from the 20 morphotypes from the lower horizon at Blue Rim...... 508

7-6. Leaf Mass per Area (MA) results for leaves from the lower horizon at Blue Rim...... 509

7-7. Mean annual temperature (MAT) estimates using leaf margin analysis (LMA) for the upper horizon at Blue Rim...... 510

7-8. Mean annual precipitation (MAP) estimates using leaf area analysis (LAA) for the upper horizon quarries at Blue Rim...... 511

A-1. Notes from the 2012 stratigraphic section including plant locality UF 19225...... 514

A-2. Notes from the 2014 stratigraphic section including plant locality UF 19297...... 520

E-1. Raw, untransformed CLAMP data...... 580

LIST OF FIGURES

Figure page

1-1. Map indicating location of Blue Rim in Sweetwater County, southwestern, Wyoming...... 61

1-2. The Blue Rim escarpment in Sweetwater County, WY...... 62

1-3. Select Blue Rim plant quarries...... 63

1-4. Stratigraphic section including plant locality UF 19225...... 64

1-5. Stratigraphic section including plant locality UF 19297...... 65

1-6. Estimated correlation of the two stratigraphic sections...... 66

1-7. Overview of topography of Blue Rim escarpment showing the approximate locations of the recent stratigraphic sections ...... 67

1-8. Scattered vertebrate and petrified wood fragments at Blue Rim...... 68

1-9. Invertebrate fossils at Blue Rim...... 69

1-10. 40Ar/39Ar geochronology...... 70

1-11. New 40Ar/39Ar ages for Blue Rim in the context of existing 40Ar/39Ar, biostratigraphic, and magnetostratigraphic age framework for the Green River and Bridger Formations ...... 71

1-12. Shaded relief map of the North American Cordillera showing the paleogeographic position of the Blue Rim (BR) relative to major paleorivers, lake basins, and tectonic elements...... 72

2-1. Morphotype Toothed 1; Macginitiea wyomingensis (Knowlton and Cockerell) Manchester...... 161

2-2. Morphotype Toothed 2...... 162

2-3. Morphotype Toothed 3 ...... 163

2-4. Morphotype Toothed 4 ...... 164

2-5. Morphotype Toothed 5...... 165

2-6. Morphotype Toothed 6; cf. Populus cinnamomoides (Lesquereux) MacGinitie ...... 166

2-7. Morphotype Toothed 7 ...... 167

2-8. Morphotype Toothed 8 ...... 168

2-9. Morphotype Toothed 9 ...... 169

2-10. Morphotype Toothed 10...... 170

2-11. Morphotype Toothed 11 ...... 171

2-12. Morphotype Toothed 12; Serjania rara MacGinitie ...... 172

2-13. Morphotype Toothed 13; “Aleurites” fremontensis (Berry) MacGinitie ...... 173

2-14. Morphotype Toothed 14 ...... 174

2-15. Morphotype Entire 1 ...... 175

2-16. Morphotype Entire 2 ...... 176

2-17. Morphotype Entire 3 ...... 177

2-18. Morphotype Entire 4 ...... 178

2-19. Morphotype Entire 5 ...... 179

2-20. Morphotype Entire 6 ...... 180

2-21. Morphotype Entire 7 ...... 181

2-22. Morphotype Entire 8...... 182

2-23. Morphotype Entire 9 ...... 183

2-24. Morphotype Entire 10 ...... 184

2-25. Morphotype Entire 11 ...... 185

2-26. Morphotype Entire 12 ...... 186

2-27. Morphotype Entire 13 ...... 187

2-28. Morphotype Entire 14 ...... 188

2-29. Morphotype HT, a new species in the tribe Homalieae (Salicaceae) ...... 189

2-30. Morphotype VCT ...... 190

2-31. Morphotype SR, Serjania rara MacGinitie ...... 191

2-32. Morphotype AF, “Aleurites” fremontensis (Berry) MacGinitie ...... 192

2-33. Morphotype PC, Populus cinnamomoides (Lesquereux) MacGinitie...... 193

2-34. Morphotype GBT...... 194

2-35. Morphotype TDA/PS ...... 195

2-36. Morphotype CBT...... 196

2-37. Morphotype RL...... 197

2-38. Morphotype TT...... 198

2-39. Morphotype ATR ...... 199

2-40. Morphotype HPT...... 200

2-41. Morphotype TCE, Cedrela schimperi (Lesquereux) MacGinitie ...... 201

2-42. Morphotype TRB...... 202

2-43. Morphotype BTBP ...... 203

2-44. Morphotype BTY ...... 204

2-45. Morphotype BTOS...... 205

2-46. Morphotype SYZ, Syzygioides americana (Lesquereux) Manchester, Dilcher et Wing ...... 206

2-47. Morphotype SYM, Symplocos incondita MacGinitie ...... 207

2-48. Specimens assigned to Morphotype “DE.” ...... 208

2-49. Specimens assigned to “MAC,” Macginitiea wyomingensis (Knowlton and Cockerell) Manchester ...... 209

2-50. Specimens assigned to morphotype “PL,” Platanus sp ...... 210

2-51. Specimen assigned to “CN,” Cedrelospermum nervosum (Newberry) Manchester ...... 211

2-52. Specimens assigned to “RN,” Rhus nigricans (Lesquereux) Knowlton ...... 212

2-53. Specimens assigned to “AT,” “Aleurites” sp...... 213

2-54. Specimens assigned to “SR-U,” Serjania rara MacGinitie...... 214

2-55. Specimens assigned to “MLA: Mac look alike.”...... 215

2-56. Specimens assigned to “PC-U,” Populus cinnamomoides (Lesquereux) MacGinitie .....216

2-57. Specimens assigned to “CS.” cf. Salix sp. / cf. Pseudosalix sp...... 217

2-58. Morphotype “OS: Odd secondaries.” ...... 218

2-59. Morphotype “ST: Saw teeth.” ...... 219

2-60. Morphotype “IT: Irregular teeth.” ...... 220

2-61. Morphotype “AV: Actinodromous venation.” ...... 221

2-62. Morphotype “PS: Parallel secondaries.” ...... 222

2-63. Morphotype “BN: Broad notophyll.” ...... 223

2-64. Morphotype “ID: Insect delight.”...... 224

2-65. Morphotype “AA: Acute apex.” ...... 225

2-66. Morphotype “SP: Stout primary.”...... 226

2-67. Morphotype “PT: Pointed teeth.” ...... 227

2-68. Morphotype “PLS: Punctate laminar surface.”...... 228

2-69. Specimens assigned to morphotype “YAB.” ...... 229

2-70. Specimens assigned to morphotype “O.”...... 230

2-71. Morphotype “Star.” ...... 231

2-72. Morphotype “Inverted triangle.” ...... 232

2-73. Specimens assigned to morphotype “Loop.” ...... 233

2-74. Specimens assigned to morphotype “Marquise.” ...... 234

2-75. Specimens assigned to morphotype “Reverse teardrop.” ...... 235

2-76. Specimens of morphotype “Eucamp.” ...... 236

2-77. Morphotype “Mesh.” ...... 237

2-78. Morphotype SYZ, Syzygioides sp ...... 238

2-79. Specimens assigned to morphotype “WSB: Widely spaced (secondaries) balloon.” ...... 239

2-80. Specimens assigned to “AL: Aristolochia like.”...... 240

2-81. Morphotype “X.” ...... 241

2-82. Specimens assigned to the legume morphotype ...... 242

2-83. Morphotype “CV: Curved venation.” ...... 243

3-1. Specimens of “Mini Spike.”...... 294

3-2. Flowers assigned to “Sunburst.” These are representative of a new species in the tribe Homalieae of Salicaceae s.l...... 295

3-3. In situ pollen extracted from the anthers of the “Sunburst” flower morphotype ...... 297

3-4. Fossils assigned to the “Poofball” morphotype ...... 298

3-5. In situ pollen viewed via SEM from UF 15761-22856...... 299

3-6. In situ pollen viewed by SEM of UF 15761N-57784 ...... 300

3-7. Flowers assigned to “Tiny 5-petal.”...... 301

3-8. Flowers assigned to “Cup-like flower with tiny stamens.”...... 302

3-9. Flowers assigned to “Petals with central vein.” ...... 303

3-10. “Large stamens” and Landeenia aralioides (MacGinitie) Manchester and Hermsen. ....304

3-11. Selection of fruits from Blue Rim ...... 305

3-12. Fruits of Macginicarpa sp. (Platanaceae) ...... 306

3-13. Fruits and seeds of cf. Ampelopsis rooseae (Vitaceae)...... 307

3-14. Fruits of Populus sp. 1 (A-C) and Populus cinnamomoides (Lesquereux) MacGinitie (D-H) ...... 308

3-15. Specimens assigned to cf. Keratospermum (A & B), Araceae (C), Lagokarpos lacustris McMurran et Manchester (D & E) ...... 309

3-16. Specimens assigned to Cluster Type 1 (A-E) and Araceae (F-H) ...... 310

3-17. Specimens assigned to “Winged Teardrop” (A-C), Beach Ball Type 1 (D & E), Beach Ball Type 2 (F), and “Tiny Winged” (G-I) ...... 311

3-18. Specimens assigned to cf. Calycites ardtunensis (A & B), “Three carpels” (C), “Two Sectioned Crescents with Tails” (D-G), and “Spikey Sun” (H & I) ...... 312

3-19. Specimens of Cluster Type 2 (A-C), Cluster Type 3 (D), and Cluster Type 4 (E-G) .....313

3-20. Specimens of Larger Spike (A & B) and Equisetum sp. (C-G)...... 314

3-21. In situ pollen from specimen UF 19225-57041 (A-C) and CT Scan images of a few reproductive structures at Blue Rim (D-I) ...... 315

3-22. Dispersed spores and pollen from UF 19404...... 317

3-23. Dispersed pollen from UF 19404...... 318

3-24. Dispersed pollen from unit 8 of the 2012/UF 19225 stratigraphic section ...... 319

3-25. Dispersed spores and pollen from unit 18 of the 2012/UF 19225 stratigraphic section ..320

3-26. Dispersed pollen from unit 18 of the 2012/UF 19225 stratigraphic section ...... 321

3-27. Dispersed spores from unit 11 of the 2014/UF 19297 stratigraphic section...... 322

3-28. Dispersed pollen from unit 11 of the 2014/UF 19297 stratigraphic section ...... 323

3-29. Spores and gymnosperm pollen from unit 15 of the 2014/UF 19297 stratigraphic section...... 324

3-30. Pollen from unit 15 of the 2014/UF 19297 stratigraphic section...... 325

3-31. Pollen from unit 15 of the 2014/UF 19297 stratigraphic section...... 326

3-32. Pollen from unit 15 of the 2014/UF 19297 stratigraphic section...... 327

3-33. Spores and gymnosperm pollen from unit 16 of the 2014/UF 19297 stratigraphic section...... 328

3-34. Pollen from unit 16 of the 2014/UF 19297 stratigraphic section...... 329

3-35. Pollen from unit 16 of the 2014/UF 19297 stratigraphic section...... 330

4-1. Map of localities in southwestern Wyoming, northeastern Utah, and northwestern Colorado where Phoenix windmillis sp. nov. flowers have been found...... 349

4-2. Phoenix windmillis sp. nov. from the Blue Rim flora of the Bridger Formation (A- D), the Wind River Formation (E), the Parachute Creek Member of the Green River Formation (F-H), and the Laney Member of the Green River Formation (I-K) ...... 350

4-3. Phoenix windmillis sp. nov. from the Fossil Butte Member of the Green River Formation ...... 352

4-4. Pollen from UF 18150-56374 ...... 353

4-5. Extant Phoenix flowers and pollen for comparison to fossil material ...... 354

5-1. Extant Iodes fruits for comparison with the fossil specimens ...... 393

5-2. Map showing the fossil localities referenced in the text ...... 394

5-3. Fruits of Biceratocarpum brownii gen. et comb. nov...... 395

5-4. Papillae of fossil and modern specimens of Icacinaceae ...... 396

5-5. Drawing of Biceratocarpum brownii gen. et comb. nov. emphasizing features observed on fossils and described in text ...... 397

5-6. Phytocrene blancoi (Blanco) Merr., Elmer 15960, Luzon Island, Philippines, MO 833710...... 397

5-7. Icacinicaryites lottii sp. nov. fruits from the Kisinger Lakes flora of Wyoming ...... 398

5-8. Selection of Iodes occidentalis sp. nov. fruits from the Blue Rim flora (Bridger Formation) in southwestern Wyoming showing notable characteristics ...... 399

5-9. Impressions of fruits of Iodes occidentalis sp. nov. from the Barrel Springs locality (Green River Formation) in Wyoming (A–C) and the Douglas Pass Radar Site II locality in Colorado (D) ...... 401

5-10. Selection of leaves of Goweria bluerimensis sp. nov. from the Blue Rim flora (Bridger Formation) in southwestern Wyoming ...... 402

5-11. Extant Iodes leaves for comparison with the fossil specimens ...... 403

5-12. Modern distribution of Iodes in central Africa, Madagascar, southeastern Asia, and the central Indo-Pacific Islands...... 404

6-1. Location of the Blue Rim site (blue dot) in Sweetwater County in southwestern Wyoming...... 457

6-2. The wood specimen of Pinaceae ...... 458

6-3. Canellaceae Xylotype 1 ...... 459

6-4. Specimens assigned to Peltophoroxylon diversiradii (Caesalpinioideae, Fabaceae) ...... 460

6-5. Specimens assigned to Peltophoroxylon diversiradii (Caesalpinioideae, Fabaceae) ...... 462

6-6. A well-preserved specimen of Edenoxylon parviareolatum (Anacardiaceae) ...... 463

6-7. Views of other specimens assigned to Edenoxylon parviareolatum ...... 465

6-8. Additional views of Edenoxylon parviareolatum ...... 467

6-9. The Incertae sedis specimens ...... 469

7-1. Leaf mass per area summary from the lower horizon at Blue Rim...... 512

7-2. Estimated paleotemperatures from nine early Eocene and PETM localities including Blue Rim (BR) ...... 513

A-1. Complete 40Ar/39Ar data results...... 524

LIST OF ABBREVIATIONS

BR Blue Rim: The name of the escarpment in Sweetwater County, southwestern Wyoming where the fossils were found.

BSR Big Sandy Reservoir

CLAMP Climate Leaf Analysis Multivariate Program

DMNS Denver Museum of Nature and Science

EECO Early Eocene Climatic Optimum, ~53-50 Ma

FLMNH Florida Museum of Natural History; Gainesville, FL

GRF Green River Formation

LAA Leaf Area Analysis, used to estimate paleoprecipitation

LM Light Microscopy

LMA Leaf Margin Analysis, used to estimate paleotemperature

MAP Mean Annual Precipitation

MAT Mean Annual Temperature

NALMA North American Land Mammal Age

PETM Paleocene Eocene Thermal Maximum, ~56 Ma

SEM Scanning Electron Microscopy

UF University of Florida, also represents the abbreviation for fossil specimens curated at the FLMNH

UCMP University of California Museum of Paleontology

USNM United States National Musuem of Natural History

Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy

THE UPPERMOST LOWER EOCENE BLUE RIM FLORA FROM THE BRIDGER FORMATION OF SOUTHWESTERN WYOMING: FLORISTIC COMPOSITION, PALEOCLIMATE, AND PALEOECOLOGY

Sarah Elizabeth Allen

May 2017

Chair: Steven R. Manchester Major: Botany

The Blue Rim flora, which includes leaves, wood, and reproductive structures, was examined to provide a broad picture of the vegetation and climate of this uppermost Lower

Eocene site in the Bridger Formation of southwestern Wyoming. The Bridger Formation, well- known for its vertebrate fossils, was deposited predominately by fluvial systems carrying sediment from the Absaroka volcanic field to the north; these sediments included tuffaceous material that was radiometrically dated to ~49 Ma. The macrofossils are preserved in two laterally extensive horizons and an isolated channel fill. The leaves, represented by at least 69 morphotypes, include taxa previously recognized in the Green River and Kisinger Lakes floras

(e.g., Populus cinnamomoides, Macginitiea wyomingensis, Serjania rara), as well as new species such as Goweria bluerimensis (Icacinaceae). Other families recognized in the macroflora include: Anacardiaceae, Vitaceae, and Ulmaceae. A new species of date palm, Phoenix windmillis, was recognized based on flowers with in situ pollen from Blue Rim and nearby sites in the Green River Formation. In total, more than 30 flower, fruit, and seed morphotypes are preserved at Blue Rim.

The species richness represented by the woods (7) is lower than that of the other macrofossils. The woods have been assigned to Pinaceae, Anacardiaceae, Canellaceae, Fabaceae, and three unidentifiable, but distinct diffuse-porous angiosperm species. The wood specimen of

Pinaceae is the only gymnosperm macrofossil recovered at Blue Rim. However, the dispersed palynoflora, likely representative of both the local and regional flora, preserves Pinus and other taxa not otherwise present in the macroflora (e.g., Carya and Alnus).

Leaf physiognomic approaches were used to estimate the paleoclimate at Blue Rim.

Mean annual temperature (MAT) estimates for the isolated channel fill ranged from ~15-20 °C.

The estimated MAT of the lower horizon ranged from ~14-18 °C; whereas the upper horizon was the coolest with MAT estimates ranging from ~13-17 °C. Estimates for mean annual precipitation at Blue Rim in the latest Early Eocene varied from 130 to 200 cm. The Blue Rim ecosystem had trees, estimated up to ~28 meters tall, which would have provided support for the climbing taxa, including the abundant fern Lygodium kaulfussi.

CHAPTER 1 GEOLOGICAL, PALEONTOLOGICAL AND PALEOCLIMATIC CONTEXT

The Eocene Bridger Formation of southwestern Wyoming provides a window to the terrestrial plant and animal community of mid-continent North America at a time when the climate was significantly warmer than today. The fauna of the Bridger Formation has been explored over many years (e.g., Gunnell, 1998), but the flora has been largely overlooked, despite its potential for documenting both the local and the regional environment.

The plant fossils described in the following chapters were collected from the lower part of the Bridger Formation (~49.0 Ma) as exposed over a ~12 km, ~100 m high escarpment called

Blue Rim (Fig. 1-1, Kistner, 1973). The Blue Rim sites are unusual in that multiple plant organs and tissues are preserved together in the same horizons (including leaves, flowers, fruits/seeds, wood, pollen, and spores). The Blue Rim flora, through its taxonomic composition and physiognomic structure, allows us to visualize the local community assemblage and climate implications and to understand how the Bridger Formation fits into the paleoecological and paleoclimatic picture of the end deposition of the Greater Green River Basin.

Part I: Regional Perspective

Topographic and Geologic Setting

Before the topography of the Rocky Mountain region began to resemble its current configuration (after the Laramide Orogeny), the Sevier Orogeny impacted the region between

~100 and 50 Ma. This fold-thrust (low angle reverse faults) belt caused crustal shortening (over

100 miles) and thickening, especially just to the west of the modern-day Rocky Mountains

(Snoke et al., 1993). These mountain building events were influenced by subduction that was occurring along the western coast of North America (Snoke et al., 1993). The Sevier Orogeny was thin-skinned (displacing the cover, rather than basement rocks) and resulted in many parallel

ridges and valleys in Nevada and Idaho (known as the Basin and Range Province, Taylor et al.,

2000; Tikoff and Maxson, 2001). The eastern margin of the Sevier Orogeny is represented by a thin-skinned fold-thrust belt along the western edge of Wyoming (DeCelles, 1994).

Wyoming and the greater Rocky Mountains lie in the Laramide Province. This area, which lies to the east of the Sevier fold-thrust belt, is composed of uplifted mountain ranges like the Wind River in Wyoming that were displaced by thrust and reverse faults in the late

Cretaceous and early Paleogene (Lillegraven, 2015). The cause of the Laramide deformation is linked to the convergence of the North American and Farallon plates along the western margin of

North America (Snoke et al., 1993; Fan and Dettman, 2009; Smith et al., 2014b). An alternative hypothesis that has been proposed as the mechanism for the Laramide deformation is the collision of the Baja BC block into what is now northern Mexico (it has since moved north to its current location as part of British Columbia and Alaska). This collision caused the lithosphere to buckle, which created numerous arches (such as the Rock Springs uplift) in the crust (Maxson and Tikoff, 1996; Tikoff and Maxson, 2001). The Laramide-aged (~75 and 45 Ma) uplifts are variously oriented across the province and are composed of a core of Precambrian basement rocks and covered by Phanerozoic sedimentary rocks (Dickinson et al., 1988; Snoke et al., 1993;

DeCelles, 1994; Maxson and Tikoff, 1996; Tikoff and Maxson, 2001). The Laramide crustal shortening (~48 km) and reverse and thrust fault uplifts were ‘thick-skinned’ as basement rocks were also displaced (Snoke et al., 1993; Maxson and Tikoff, 1996; Lillegraven, 2015). Vertically uplifted basement rocks display brittle fracturing while the younger sedimentary cover folded in a ductile fashion (Snoke et al., 1993). The Laramide deformation overlapped in time with the

Sevier tectonic activity to the west (Dickinson et al., 1988; Snoke et al., 1993). More

specifically, the Wind River Range was uplifted in the Late Cretaceous whereas the Bighorn and

Beartooth Mountains were uplifted in the early Eocene (Snoke et al., 1993).

Most of the sedimentary basin deposits in Wyoming and throughout the Rocky

Mountains are from basins that formed adjacent to the eroding Laramide uplifts (Dickinson et al.,

1988; Snoke et al., 1993). During the peak of the Laramide Orogeny (late Paleocene/early

Eocene), the mountains would have had high relief, but the basins are interpreted to have been near sea level as this region had yet to be uplifted to its present elevation (see further discussion of paleoaltitude below, Snoke et al., 1993).

Weaknesses in the bedrock caused by both the Laramide Orogeny and extensional processes via low angle normal faults led to volcanism in the region in the Cenozoic (Snoke et al., 1993). Volcanism in the Black Hills, Absaroka (WY-MT), Challis (ID), and Kamloops

(British Columbia) regions occurred during the early and middle Eocene. The Absaroka

Volcanic Province in northwest Wyoming and southwest Montana created 10,000 foot high strato-volcanos that were quickly eroded (Snoke et al., 1993). These volcanoes, along with those of the Challis volcanic field in Idaho, provided much of the volcanically derived sediment that makes up the Bridger Formation (Murphey and Evanoff, 2011).

As the Laramide Orogeny ceased, the basins between many of the mountain ranges filled with large lakes. This includes the Eocene Lake Gosiute in the Green River Basin of southwestern Wyoming, which is represented by the lacustrine deposits of the Green River

Formation (Luman Tongue, Tipton, Wilkens Peak, and Laney Members; Smith et al., 2003).

There are two hypotheses as to why the lakes formed: Either the drainage was reversed as the foreland basins were tilted to the west or, alternatively, the basins may have been warped from below as underground heat intensified due to the volcanism (Snoke et al., 1993). Lacustrine

deposits were later buried by volcanic and clastic (stream erosion) deposits (e.g., Bridger

Formation).

The Bridger Formation is located in the Green River Basin of southwestern Wyoming. It both overlies and lies adjacent to the Green River Formation and a bit of the Wasatch Formation

(Krishtalka et al., 1987; Robinson et al., 2004). Topographically the Greater Green River Basin and the Bridger Formation are surrounded by the Uinta Mountains to the south, the Wyoming overthrust belt to the west, the Wind River Range to the north, and the Rock Springs uplift to the south and east (see Figure 1 in Murphey et al., 2011). The Greater Green River Basin is a large asymmetrical syncline that formed during the Laramide Orogeny. It has a north-south axis with shallow dips and spans just over 32,000 km2 (Murphey and Evanoff, 2011). Over 80 percent of the rocks in the Greater Green River Basin are Eocene in age (including the Bridger Formation) and sediments are more than 10,000 feet (>3048 m) thick in places (Roehler, 1992a). This large basin is further divided into four smaller basins including the Green River Basin to the west of the Rock Springs uplift (Murphey and Evanoff, 2011; Murphey et al., 2011). During the

Laramide tectonic events (including uplift of nearby mountain ranges), fluvial and lacustrine sediment deposition in the Greater Green River Basin was almost continuous (Murphey and

Evanoff, 2011; Murphey et al., 2011).

The well-known Green River Formation (GRF) represents a dynamic large lake system that spanned parts of Colorado, Utah, and Wyoming during the early Eocene from approximately

53.5 to 48.5 Ma (Smith et al., 2003). Lake Gosiute occupied much of the Greater Green River

Basin in southwestern Wyoming during this time interval. In the Green River Basin of Wyoming the formation is composed of six members or tongues (Bradley, 1963). The Tipton Shale

Member preserves the first great expansion of the lake, which was only exceeded in aerial extent

by the last extension (Laney Shale Member). After the expansion that deposited the Tipton Shale

Member, the lake shrank and evaporates were deposited as the Wilkins Peak Member (Bradley,

1963; Smith et al., 2003). The Laney Member is the youngest unit with a large aerial extent and preserves the final significant expansion of the lake (Murphey et al., 2011). Laney sediments intertongue with the fluvial sediments of the lower Bridger Formation (Bradley, 1963; Smith et al., 2003; Smith et al., 2014a).

Paleolatitude. Estimates for the paleolatitude of southern Wyoming in the early Eocene have varied, but it was likely similar to its current position (N 41.82° at Blue Rim, Wolfe et al.,

1998). However, Roehler (1993) commented that the Greater Green River Basin was 5 to 8° south of its present location at ~35 °N, whereas Fricke (2003) estimated it was ~ N 44° based on the work by Scotese. More recent work based on summarizing information from paleomagnetic data and paleogeographic reconstructions has suggested that the Green River Basin was slightly further south than its present location in the early Eocene at ~41 °N (Hyland and Sheldon, 2013), but others have suggested it was ~6° further north than today (Fan and Carrapa, 2014).

Paleoelevation. Estimates of paleoelevation have varied widely and have used oxygen isotope data, paleoenthalpy estimates from CLAMP analyses, lapse rates from MAT data, and by examining the flora and fauna present.

Some analyses using oxygen isotopes have suggested the Green River Basin was surrounded by large mountains, coinciding with the Laramide Orogeny. Norris et al. (1996) and

Dettman and Lohmann (2000) estimated the mountains surrounding the Green River Basin were on the order of 2500 m to greater than 3000 m with snow present. However, the high elevations from low oxygen isotope values (e.g., Norris et al., 1996; Dettman and Lohmann, 2000) in the

Green River Basin could be due the presence of a secondary precipitate in the samples,

evaporation, source water, and numerous other factors (Morrill and Koch, 2002; Fan and

Carrapa, 2014). Unalterated aragonite bivalves did not yield low (< -12‰) δ18O values, although some samples with a diagenetic overprint did (Morrill and Koch, 2002). The δ18O values obtained from unaltered samples were in the range of precipitation from low elevation continental areas without evidence for snowmelt (Morrill and Koch, 2002). Fricke (2003) also estimated lower elevations with basin floors (including the Green River) ~475 m and the surrounding mountains (e.g., Bighorn) up to 1000 m.

Carroll et al. (2008) documented a shift in δ18O values obtained from calcitic mudstone over ~100,000 years in the LaClede Bed of the Green River Formation at ~49 Ma. This shift toward lower δ18O is likely representative of water entering the basin that originated from high elevation areas. However, the extensive drainage into Lake Gosiute suggests water could have traveled in via rivers and streams from as far away as north central Idaho and is not necessarily representative of local high relief (Carroll et al., 2008). The adjacent Laramide ranges could still have been low elevation, even if the lake water contained evidence of snowmelt (Carroll et al.,

2008).

Paleoelevation estimates from mean annual temperature (using lapse rates) and enthalphy estimates using leaf physiognomic approaches (e.g., Gregory-Wodzicki, 1997) have both been criticized as inaccurate. For example, published estimates of paleoelevation for the same paleobotanical site (Florissant) using MAT and enthalphy have been over 3 km different from each other (Meyer, 2007).

Wolfe et al. (1998) used enthalpy estimated from CLAMP analyses to determine paleoaltitude; for example, the Little Mountain Site (GRF, Laney and Wilkins Peak Members,

Wilf, 2000) was estimated to be to be 2.1 ± 0.8 km. Peppe et al. (2010) examined paleoaltitude

estimates using enthalpy values obtained from a CLAMP analysis. They found that leaf area is significantly underestimated using the CLAMP size categories (as opposed to digitally measuring the leaves), which can result in large differences in resulting elevation estimates.

Enthalpy results are lower when using the CLAMP size categories and higher when the same leaves are measured digitally (Peppe et al., 2010). The error on a paleoaltitude estimate using paleoenthalpy from a traditional CLAMP analysis should be ± 1.98 km (Peppe et al., 2010), which is even higher than the previously estimated error of ± 0.91 km (Forest et al., 1999).

Using our understanding of flora, fauna, and sedimentology, hypothesized estimates of the elevation of the Green River Basin have been much lower than those from some oxygen isotope analyses (e.g., Norris et al., 1996; Dettman and Lohmann, 2000). For example, the surface elevation of the Green River lakes has been hypothesized to be approximately 1,000 ft

(305 m, Bradley, 1963; MacGinitie, 1969). The mostly fluvial sediments at Blue Rim were likely slightly higher in elevation, but still low. MacGinitie (1969) noted that the overall elevation in the early Eocene Green River Formation was much lower than present (>2,000 feet lower) with fewer large mountain chains. More recently the elevation of the Green River and Washakie basins was estimated to be 1200-1400 m (Thrasher and Sloan, 2010). Other evidence suggesting the area was low in elevation (<1 km) includes the presence flora and fauna that required warm temperatures (e.g., crocodiles, palms). In addition, the Green River lakes collected drainage from a wide area, which suggests they were a low point and the region was more tectonically active after the Bridger was deposited (M.E. Smith personal communication, Sept. 2016). The Farallon slab was removed from underneath Wyoming after the deposition of the Bridger sediments which led to an ~1 km uplift in the area (M.E. Smith personal communication, Sept. 2016).

Geology and Sedimentological Origins of the Bridger Formation

The mostly fluvial mudstones, siltstones, sandstones, and limestones of the Bridger

Formation can be found both lateral to and above the lacustrine Green River Formation

(Murphey and Evanoff, 2011). Fewer lacustrine sediments were deposited as the Green River

Basin was filled with reworked volcanic debris deposited by deltas and fluvial systems; Lake

Gosiute shrank and was isolated to the southeast corner of the basin (Sullivan, 1980; Roehler,

1993; Smith et al., 2008). This change from lacustrine to fluvial sedimentation forms the rough boundary between the Green River and Bridger Formations (Buchheim, 2000; Chetel and

Carroll, 2010). The lower portion of the Bridger was deposited laterally to the Laney Shale

Member of the GRF and many of the limestones in the lower Bridger intertongue with Green

River facies. The Sage Creek limestone, a unit that divides two subunits (B & C) of the Bridger

Formation, represents the last extension of Lake Gosiute. Lakes that formed in the Greater Green

River Basin after the final retreat of Lake Gosiute were smaller with a shorter duration (Murphey et al., 2001).

The ~842 m thick sediments that comprise the Bridger Formation are mainly mudstone with intermittent interbedded sandstone, limestone, marlstone, siltstone, and thin beds of tuff

(Groll and Steidtmann, 1987; Roehler, 1992a, b, 1993; Buchheim, 2000; Murphey and Evanoff,

2011). The mudstone has a high percentage of smectite which swells when wet and causes the popcorn surface common throughout the Bridger badlands (Alexander and Burger, 2001).

Murphey (2001) noted the sediments of the Bridger Formation at Omomys Quarry in Uinta

County, Wyoming consisted of green to brown mudstones and claystones. Ribbon or sheet sandstones were sometimes present along with widespread micritic silicified limestones in addition to rare, thin, but widespread ash fall tuffs. Micrite forms when sediments rich in calcium carbonate accumulate on lake bottoms and are incorporated into muddy shorelines during water 31

level fluctuations, resulting in shoreline deposits of calcareous mudstones (Murphey et al., 2001).

These alkaline, low energy conditions provide a good environment for vertebrate deposition

(Murphey et al., 2001).

Stratigraphic work has examined fluvial Bridger A sediments and part of the lacustrine

Laney Member of the GRF near Opal, Lincoln County, Wyoming (Wood, 1966; Gunnell and

Bartels, 1994) about 60 km west of Blue Rim. In this area, Bridger sediments are composed of claystones, siltstones, marlstones, and sandstones (mostly as lenticular channel deposits) deposited by meandering streams with heavy sediment loads, floodplains, deltas, and shallow lakes with minimal paleosol development (Wood, 1966; Gunnell and Bartels, 1994). The Bridger

Formation deposits in the Opal area are mostly volcanic material reworked by streams; however, clay ball conglomerates were preserved in the channel sandstones (Wood, 1966). Such coarse and high energy deposits were not observed at Blue Rim, even though the predominant depositional environments are likely similar between the two sites based on the presence of similar rock types, their overlapping ages, and geographic proximity.

The Bridger Formation preserves evidence of deltas and both active and meandering streams punctuated with periods of flooding as Lake Gosuite transgressed and regressed

(MacGinitie, 1969; Kistner, 1973; Sullivan, 1980; Groll and Steidtmann, 1987; Roehler, 1992b;

Buchheim, 2000). The widespread limestones (often with ostracods) in the Bridger Formation usually represent basin wide shallow lakes as Lake Gosiute transgressed (Groll and Steidtmann,

1987), but these are a different lithology than the majority of the main body of the Green River

Formation (Brand, 2007). The water depth remained shallow, but the flooding was either quiet and calm (lake transgression) or turbid due to excessive stream discharge (MacGinitie, 1969).

The shallow lakes were filled in by the volcanoclastic debris of the Bridger Formation and returned when basin subsidence was greater than sediment input (Brand, 2007).

Sediments in the Bridger Formation are derived mostly from the Absaroka volcanic field

(northwestern WY), via fluvial processes (Alexander and Burger, 2001; Murphey and Evanoff,

2011; Murphey et al., 2011). Although the majority of the sediments in the Bridger Formation of volcanic origin are from the Absaroka volcanic field, the ash-fall tuffs, which make up only a fraction of Bridger deposits, are most likely from the Challis volcanic field in central Idaho based on their mineralogy (Murphey et al., 2011).

Overall, the sediments in the Bridger indicate fluvial (often composed of volcanoclastic material including tuffs) and floodplain deposits punctuated by occasional widespread lacustrine events (Kistner, 1973; Sullivan, 1980; Roehler, 1992b, a; Alexander and Burger, 2001; Clyde et al., 2001).

Stratigraphic Members of the Bridger Formation

Hayden named the Bridger Group in 1869, with the type area at Church Buttes Station,

Wyoming (Krishtalka et al., 1987; Robinson et al., 2004; Murphey et al., 2011). In 1885, O.C.

Marsh termed the Dinoceras (unitathere; large hoofed mammal with three pairs of horns) beds in the area, the “Bridger series” (Krishtalka et al., 1987). The stratigraphy of the Bridger Formation was first published in 1909 by Matthew. He divided the formation into five (A-E) informal members from lowest to highest on the basis of extensive white marker beds (usually lacustrine limestones) that could be traced laterally (Matthew, 1909). Some of the lettered sections were further subdivided using resistant marl beds (Krishtalka et al., 1987; Robinson et al., 2004;

Murphey et al., 2011). There are now 25 recognized marker beds in units B-D of the Bridger

(Murphey et al., 2001).

Bridger A and B were later grouped into the Blacks Fork Member, while Bridger C and

D were grouped into the Twin Buttes Member based on faunal similarities observed by H.E.

Wood (Krishtalka et al., 1987; Murphey et al., 2001; Robinson et al., 2004; Murphey and

Evanoff, 2011). In 1981, West and Hutchinson termed Bridger E the Cedar Mountain Member, but it was renamed to the Turtle Bluffs Member to avoid confusion with the formation in Utah of the same name (Murphey et al., 2001; Robinson et al., 2004; Murphey and Evanoff, 2011).

The Bridgerian North American Land Mammal Age

Although the lithologic members of the Bridger Formation were divided up using laterally extensive marker units, they cannot be correlated to broader temporal events without incorporating other information including biostratigraphy. The North American Land Mammal

Ages (NALMA) have been the main tool for correlating Cenozoic terrestrial strata in the greater

Rocky Mountain region. The Bridger Formation is the stratotype for the Bridgerian NALMA, and provides the basis for recognizing Bridgerian aged sediments in other parts of WY, as well as UT, CO, TX, OR, NJ, and parts of Canada (Krishtalka et al., 1987).

The Bridgerian is preceded by the Wasatchian (substage Lostcabinian) and followed by the Uintan NALMA. The boundary between the Bridgerian and Wasatchian stages can be found in the Cathedral Bluffs Tongue of the Wasatch Formation and the Huerfano Basin in southern

Colorado (Krishtalka et al., 1987; Robinson et al., 2004). The fauna that represents the transition between the two NALMAs can also be recovered in the Wind River Formation, at the South Pass locality (WY) in the Greater Green River Basin, and in other places (Robinson et al., 2004). The

Wasatchian/Bridgerian boundary (note that the Bridgerian NALMA does not coincide perfectly with the deposition of the Bridger Formation) has most recently been placed at 50.56 ±0.13 Ma based on the Grey Tuff of the Wilkins Peak Member of the Green River Formation (Smith et al.,

2003). The first appearance of Helohyus, Homacodon, Hyrachyus, Megadelphus, Omomys, 34

Palaeosyops, Pantolestes, Smilodectes, Trogosus, and Washakius defines the onset of the

Bridgerian NALMA (Robinson et al., 2004). There are also taxa that carry through from the

Wasatchian and taxa whose last appearance datum occurs during the Bridgerian.

In addition, magnetostratigraphy has been used in the last 20 years to try to connect the

NALMAs with the Geomagnetic Polarity Time Scale (GPTS). Clyde and colleagues (1997;

2001) examined the Wasatchian/ Bridgerian boundary in the Wasatch and Green River

Formations within the Green River Basin. Paleomagnetic cores were obtained that could be correlated to biostratigraphically controlled mammalian fossil localities (Clyde et al., 1997;

Clyde et al., 2001). Clyde et al. (2001) concluded that the Wasatchian/Bridgerian boundary is most likely at ~52 Ma which falls in the Ypresian stage and Chron C23r. If the

Wasatchian/Bridgerian boundary falls in Chron C23r , then it also corresponds to other indicators that suggest that the Chron C23r preserves the warmest interval in the Cenozoic (Clyde et al.,

2001).

More recently, the Bridgerian NALMA has been subdivided into ‘biochrons’ of Br0,

Br1a, Br1b, Br2 and Br3. Br0 and Br1a form the preceding Gardnerbuttean substage and are not found in the Bridger Formation. Br1b and Br2 comprise the Blacksforkian Substage (Robinson et al., 2004; Gunnell et al., 2009). Br1b, or the lower Blackforkian, is equivalent in time to Bridger

A (including much of Blue Rim), as named by Matthew in 1909. The faunal components

Anaptomorphus westi, Bathyopsis middleswarti, and Smilodectes mcgrewi are restricted to Br1b

(Robinson et al., 2004). Br2, or the upper Blackforkian, is equivalent to Matthew’s Bridger B.

The Lyman Limestone is the boundary between Bridger A and B. Bridger A was once regarded as having few fossils, but more work has uncovered a unique mammal fauna (McGrew and

Sullivan, 1971; Murphey et al., 2011). Br3 has been termed the Twinbuttean substage (Robinson

et al., 2004) and includes Matthew’s Bridger C and D. The upper Bridger Formation, Matthew’s

Bridger E, represents the Turtle Bluff Member and falls in the Uintan NALMA (Murphey et al.,

2011). There are numerous stratigraphic sections that preserve part of the Bridgerian/Uintan

Boundary, but that is outside the scope of this review (Krishtalka et al., 1987; Robinson et al.,

2004).

The Bridger Formation is the stratotype for the Bridgerian NALMA (Murphey and

Evanoff, 2011) and accordingly it is well-known for its abundance of high quality vertebrate faunas. Each biochronological division of the Bridger has its own type locality; for example, the type locality for Br1b is the RC Bench section in Lincoln County, Wyoming (Gunnell et al.,

2009). It is thought that the Bridger Formation (~3.2 Ma) may only span ~60% of the Bridgerian

NALMA; Bridger E (Turtle Bluff Member) is now assigned to the Uintan NALMA (Robinson et al., 2004). Based on the information available at the time, Krishtalka et al. (1987) suggested the

Bridgerian NALMA commenced at ~51 or 50.5 Ma and lasted 2-3 Ma. However, more recent work suggested that the Bridgerian NALMA may be as long as 5 Ma spanning from approximately 51-46 Ma (Robinson et al., 2004).

Radiometric Dating

Murphey et al. (1999) estimated that the Bridger Formation spanned ~3.5 m.y. from

~49.09 to 45.57 Ma. Other work suggests the deposition of the Bridger Formation commenced prior to 50 Ma (Krishtalka et al., 1987; Alexander and Burger, 2001).

Radiometric dates on selected tuffs within the Bridger Formation provide a broad temporal context for paleontological investigations. No radiometric dates from Bridger A, which yields most (or all) of the flora dealt with in this dissertation, have been published (but see new data below). However, an 40Ar/39Ar age of 48.27 Ma was estimated from a sanidine from the stratigraphically younger Church Butte tuff (Bridger B) elsewhere in the basin (Murphey et al., 36

2011). The Henrys Fork tuff at the base of Bridger C provided an 40Ar/39Ar estimate of 47.22 Ma

(Murphey et al., 2011). Furthermore, a tuff at the base of Bridger E (on Sage Creek Mountain) has been dated using 40Ar/39Ar to 46.16 ± 0.44 Ma by Murphey and Evanoff (2007). Using this information, we can infer that the Blue Rim sediments (Bridger A) are older than 48.27 Ma. In addition, the Big Island Tuff in the Wilkins Peak Member of the Green River Formation, considered approximately laterally correlative with the lower Bridger Formation (Alexander and

Burger, 2001), has been dated to 50.4 ± 1.1 Ma and 50.l ± 1.2 Ma (Krishtalka et al., 1987).

Early Paleontological Work in the Bridger Formation

Geological and paleontological work has been occurring in the Bridger Formation since it was first explored in the early 20th century (as reviewed by Kistner, 1973; West, 1976; Sullivan,

1980; Roehler, 1992a; Chetel and Carroll, 2010). The first European to visit the Green River

Basin was John Colter in 1807. A trapper, Jack Robinson, was the first to take note of fossils in the Bridger Formation in the late 1860s (Murphey and Evanoff, 2011; Murphey et al., 2011).

F.V. Hayden collected fossil vertebrates in the Bridger Formation in the 1860s and 1870s which were studied by Joseph Leidy (Murphey and Evanoff, 2011). Leidy was the earliest researcher to formally describe a fossil from the Bridger Formation; which happened to be Omomys carteri, the first fossil primate described from North America. Other surveys of the Bridger Formation were conducted by E.D. Cope and C. King; King sent his fossils to O.C. Marsh for study

(Murphey and Evanoff, 2011). Although these early vertebrate fossils are valuable for the recognition of various new taxa, they were not collected in a rigorous stratigraphic way. The first stratigraphic paleontological work in the Bridger Formation was conducted by Granger and

Matthew (under the direction of H.F. Osborn) in the early 1900s (Murphey and Evanoff, 2011;

Murphey et al., 2011). Matthew’s (1909) monograph summarized not only some of the paleontological specimens from the Bridger Formation, but also established the subdivisions A-E 37

in the Bridger Formation (described previously). The rich vertebrate fauna of the Bridger

Formation continues to attract the attention of vertebrate paleontologists today (Murphey and

Evanoff, 2011).

Fossil Fauna and Flora in the Bridger & Nearby Localities: 20th and 21st Centuries

Vertebrates. Ample fossils in both aquatic and terrestrial habitats provide evidence for a favorable environment in the Greater Green River Basin (Murphey and Evanoff, 2011; Murphey et al., 2011). The Bridger Formation preserves one of the world’s most diverse middle Eocene mammalian faunas with approximately 86 species, 67 genera, 30 families and 13 orders represented (Murphey et al., 2001; Murphey et al., 2011). For example, work in the Grizzly

Buttes area of the Bridger Formation has recovered primates, creodonts, carnivores, rodents, palaeanodonts, perissodactyls, and artiodactyls (Alexander and Burger, 2001).

The vertebrate fauna in the Opal, WY area of the Bridger Formation includes mammals, fish (e.g., gar), crocodiles, and turtles (Wood, 1966; Gunnell and Bartels, 1994). The mammal fossil specimens, recovered from subaerial or fluvial sediments, included 27% primates, 21% rodents, and 16% perissodactyls; these three groups were the most taxonomically diverse

(Gunnell and Bartels, 1994). Bridger A/Br1b can be partially recognized by the FAD (first appearance datum) of the following: Sinopa, Thinocyon, Microsus, Leptotomus, Metacheiromys, and Pantolestes (Gunnell and Bartels, 1994). The combination of arboreal (primates and some rodents), terrestrial, and aquatic species suggests a heavily forested floodplain environment

(Wood, 1966; Gunnell and Bartels, 1994). These taxa also suggest the climate was at least

temperate to subtropical1 with ample moisture (Wood, 1966; Gunnell and Bartels, 1994). Due to the geographic proximity of Opal and Blue Rim, separated by about 60 km, it seems likely that climate conditions were similar. In addition, the lake margin environments found at Omomys

Quarry in Uinta County, Wyoming are also thought to be forested based on the presence of arboreal mammals, wood fragments, and ferns (Murphey et al., 2001).

The warm temperatures around the Wasatchian/Bridgerian boundary also coincide with a faunal transition. Gunnell (1997) noted that only 22% of the genera overlap between the

Wasatchian and Bridgerian NALMAs. Other work suggests that reptiles and tropical habitats were at their widest extent during this warm interval (Clyde et al., 2001). The Wasatchian and

Bridgerian vertebrate fauna of the Little Muddy area (including at Desertion Point) in the southwestern Green River Basin in Lincoln and Uinta Counties has been studied (Zonneveld,

1994; Zonneveld et al., 2000). This area includes fluvial Bridger A sediments preserved as the

Whiskey Butte Bed (Zonneveld, 1994). The FAD of the mammals Orohippus pumilus, Omomys carteri, Leptotomus parvus, and Washakius insignis occurs in Bridger A/1b sediments and

Notharctus robinsoni is also present in this area (Zonneveld, 1994; Zonneveld et al., 2000). In total, three species of fish, 18 species of reptiles, 40 species of mammals, and one bird species have been documented from the Little Muddy area (Zonneveld et al., 2000).

Faunas preserved in basin margins sometimes vary significantly from those preserved in the basin center (Black, 1967; Gunnell and Bartels, 2001). Basin margins are closer to sediment sources and often preserve higher energy depositional environments and more heterogeneous

1 Although the term “subtropical” can have various definitions, most authors do not define their interpretation. MacGinitie (1969) defined subtropical as a MAT of ~15.6-21.1 °C and a CMMT >12.8 °C. In a later work, MacGinitie (1974) defined subtropical as a MAT between 15-19 °C and a CMMT 6-10 °C. More recent interpretations have defined subtropical as a MAT >18 °C with a WMMT >22 °C and a CMMT between <18 °C (noaa.gov, Kottek et al., 2006). The paleoclimate results from Blue Rim (see Chapter 7) generally fall within these definitions of subtropical.

habitats; these areas may be a source of speciation (Gunnell and Bartels, 2001). For example, when Gunnell and Bartels (2001) looked at a basin margin habitat, specifically the Bridgerian

South Pass area (Wasatch and Bridger Formations) of the northeast Green River Basin, they found a different fauna than the in basin interior. Whereas amphibians, birds, and snakes are rare in the basin center, they are common in the marginal sediments at South Pass (Gunnell and

Bartels, 2001). In contrast, turtles and crocodiles are common in the basin center and rare in basin margins, but pristichampsines (crocodile relative) are more abundant in basin margin collections (Gunnell and Bartels, 2001). Species represented in basin margins often have more morphological variation than those in basin centers, likely due to the habitat heterogeneity

(Gunnell and Bartels, 2001). Basin margins may have also acted as refugia (Gunnell and Bartels,

2001). Interestingly, whereas magnetic reversal patterns are in strong agreement in different parts of the Green River Basin (Clyde et al., 1997; Clyde et al., 2001) the FAD and LAD (last appearance datum) of various taxa does not seem consistent. This provides additional support to the hypothesis that ecological habitats were quite variable across the Green River Basin.

Invertebrates. Invertebrates preserved in the Bridger Formation near Opal, WY include

Elliptio (Fam. Unionidae, Class Pelecypoda), Goniobasis (now Elimia, Fam. Pleuroceridae,

Class Gastropoda), as well as rarer Physa sp. (Fam. Physidae) and representatives of the

Planorbidae family (Wood, 1966). Wood (1966) noted that the aquatic invertebrates were not usually found in the same sediments as the mammal remains. Hanley (1974, 1976, 1977) examined the non-marine invertebrates of the Green River and Wasatch Formations. Pond facies surrounding former Lake Gosiute have bivalves and gastropods including species of Physa,

Biomphalaria, and Omalodiscus. Plesielliptio is representative of the invertebrates found in fluviatile habitats, whereas terrestrial gastropods including species of Oreoconus are found in

alluvial plain deposits (Hanley, 1976). Paludal environments in the Green River and Wasatch

Formations lack mollusks. Viviparus trochiformis, Goniobasis tenera (now Elimia tenera), and

Plesielliptio have been recovered in shoreline areas of former Lake Gosiute. Just below the shoreline areas, sublittoral habitats preserved Valvata, Goniobasis, and Pisidiidae (Hanley,

1976). In general, vertebrate and invertebrate fossils in the Bridger are most frequently encountered in low energy, marginal shoreline facies (Paul Murphey, personal communication,

July 2014).

Plants. Plant families that have been identified from late Paleocene and Eocene localities near Blue Rim include ferns and fern relatives (e.g., Polypodiales, Equisetaceae), conifers (e.g.,

Cupressaceae), and diverse angiosperms: Betulaceae, Cornaceae, Lauraceae, Zingiberaceae,

Magnoliaceae, Platanaceae, Juglandaceae, and Anacardiaceae among others (Kistner, 1973; Wilf et al., 1998b; Wilf, 2000).

Bradley (1963) and McGrew and Casilliano (1975) discussed the flora surrounding former Lake Gosiute and Fossil Lake in the Green River and Fossil Basins, respectively. They relied on the work of earlier paleobotanical studies (e.g., Brown, 1929; Wodehouse, 1932, 1933;

Brown, 1934; MacGinitie, 1969). The shores of the former Lake Gosiute were likely a cypress swamp, which transitioned to a more diverse flora including ferns, palms (on sandy soil), and a diverse dicotyledonous angiosperm assemblage in the adjacent alluvial plain (Bradley, 1963).

Higher elevation areas around the lake would have had taxa including Quercus, Acer, and Carya.

Even higher, in drier areas, Pinus would have been present, with Picea and Abies occupying the highest elevations (Bradley, 1963).

McGrew and Casilliano (1975) commented that the flora of Fossil Basin was a mixed forest composed of species from warm and wet lowlands and cooler, drier uplands. The

surrounding highlands were estimated to reach 6,000 to 8,000 feet (~1830 to 2440 m) and contained Picea, Abies, and Pinus (McGrew and Casilliano, 1975). The lower slopes were thought to support deciduous tree species including Quercus, Ulmus, Acer, and Fagus. Closest to the lake margin, palms, Salix, Ficus, and other taxa resided in subtropical conditions. The palynoflora included Ephedra (Wodehouse, 1933), suggesting occasional dry periods, but

McGrew and Casilliano (1975) note that extended dry periods were not present locally as there are no evaporite deposits. The flora and paleoclimate in Fossil Basin during deposition of the

Green River Formation was interpreted to be similar to the present day Gulf Coast with elements from the Appalachian Mountains (McGrew and Casilliano, 1975). Even though previous authors

(e.g., Brown, 1929; Wodehouse, 1932; Brown, 1934; MacGinitie, 1969) assigned fossils to

Quercus and Acer, more recent evaluations of Green River fossils have not recovered any validly identified oaks or maples.

Zonneveld (1994) studied the Wasatchian and Bridgerian mammal fauna at Desertion

Point in the Little Muddy area in the southwestern part of the Green River basin. This area includes Bridger A sediments preserved as the Whiskey Butte Bed—a fluvial interval during the regression of the Lake Gosiute. There were some poorly preserved plant fossils in this area including wood, root traces, other plant fragments, and a putative Celtis endocarp (likely an

Iodes fruit). Zonneveld (1994) also mentioned that, “The Paleobotany of the Wasatch, Bridger, and Green River Formations needs to be studied” (pg. 201).

Forty specimens of poorly preserved silicified “dicot” wood, representing at least two different taxa were found in Omomys quarry, Uinta County, Wyoming. Chara sp. (stonewort) and Dennstaedtiopsis aerenchymata (fern) were also recovered at this site (Murphey et al.,

2001). In general, fossilized wood is often found around the lacustrine deposits in the Bridger

(Paul Murphey, personal communication, July 2014). The most comprehensive treatment of the

Green River leaf flora was completed by MacGinitie in 1969. A more detailed comparison of the

Blue Rim flora and MacGinitie’s (1969) monograph of the Green River flora is in Chapter 7.

Regional Paleoenvironments and Paleoclimate Estimates

The Eocene epoch, during which the Blue Rim flora existed (~49.0 Ma), is known to have been considerably warmer than today; the late Paleocene into early Eocene is considered a hothouse or greenhouse (Wing and Greenwood, 1993). In the Eocene, evidence suggests that all glacial ice was absent, winters were frost-free (Wilf et al., 1998a), and rainfall varied, but desert- like conditions were rare or very local (Wing and Greenwood, 1993; Wilf et al., 1998b). It was thought that the climate was warm and humid with ample vegetation (Sullivan, 1980).

Using plant fossils. Within the United States, the Rocky Mountain region has had the largest climatic and vegetational changes since the early Paleogene (Wing, 1998a). The early

Eocene has been noted as the time of maximum interchange between coastal and interior floras.

Even frost intolerant or sensitive taxa were able to migrate north and inland because of the warm temperatures (Wing, 1998a). However, the early Eocene was also tectonically active with volcanic activity contributing to orogenic events, which created rain shadows and cooler and drier interior climates (Wing, 1998a).

Climate predictions for the early to middle Eocene Greater Green River Basin have varied (Leopold and MacGinitie, 1972). Roehler (1993) noted that the analysis of the mega and micro plant fossil material in the Greater Green River Basin is the best and most reliable data about the paleoclimate and suggested that the climate during the deposition of the Green River

Formation was warm temperate to tropical. Leopold and MacGinitie (1972) examined pollen samples from the Wasatch and Green River Formations and estimated that the climate in the early Eocene was subtropical to warm temperate with a mean annual temperature (MAT) of 55 43

°F (~12.8 °C). The Laney Member of the GRF, which is closest in age and geographic position to the Blue Rim site of the Bridger Formation, suggested slightly cooler subhumid conditions

(Leopold and MacGinitie, 1972). Mean annual precipitation (MAP) declined from an estimated

>40 inches (101.6 cm) in the early Eocene to 25-35 inches (63.5–88.9 cm) in the middle Eocene

(Roehler, 1993).

The flora from the Washakie Basin to the east of Blue Rim (late Paleocene-early Eocene) indicated a MAT of 19.5 °C and a MAP of 137 cm, which suggests the climate was subtropical, humid, with minimal frost, and ample moisture: essentially a forested floodplain (Wilf et al.,

1998b). Wilf et al. (1998b), also noted that the nearest living relatives of the fossil plants indicated wet conditions, because of the presence of ferns and Equisetum. Wilf (2000) examined the lacustrine Green River Little Mountain locality in southwestern Wyoming and also found frost-free, subtropical, warm climates with a MAT of 19.6 °C and MAP 75.8 cm. These findings are consistent with those of MacGinitie (1969), who estimated the MAT to be 67 °F (19.4°C).

Ferns, hornworts and horsetails show that it was moist, while palms and gingers (e.g.,

Zingiberopsis isonervosa Hickey) provide evidence of a frost-free climate (Wilf, 2000).

Nichols (1987) examined the palynoflora from the late Early Eocene Vermilion Creek coal bed in the upper Niland Tongue of Wasatch Formation in the eastern part of Sweetwater

County, WY. This late Early Eocene (~51 Ma) palynoflora was deposited in a swamp adjacent to a freshwater lacustrine environment (Nichols, 1987). The floral elements including Platycarya suggested high humidity conditions, with lots of summer rainfall, no freezing temperatures, and mean annual temperatures between 13 and 15 °C (Nichols, 1987).

Bay (1969) examined the stratigraphy of Eocene rocks in the Lysite Mountain area (Oak

Creek Mountains) of Wyoming and estimated warm temperate to subtropical conditions based on

examinations of ~350 plant fossils. There were approximately two dozen plant species including

Asplenium, Juglans, and Persea (Bay, 1969).

Evaporites are present in both the Green River and Bridger Formations (Kistner, 1973;

Smith et al., 2003; Smith et al., 2008). Traditionally, evaporite minerals provide strong evidence for arid climates. For example, large beds of gypsum can be found in some of the younger

Bridger deposits (Turtle Bluff Member) and this has partially led to the hypothesis that the flora transitioned from a tropical forest to a savannah from the early to middle Eocene (Murphey et al.,

2011). However, all of the floral paleoclimate analyses in the southern Green River Basin indicate temperature and precipitation estimates above 19 °C and 80 cm/year, respectively, indicating a humid and subtropical climate. The paleobotanical data consistently indicate moist conditions, whereas some sedimentary units indicate arid conditions (see Smith et al., 2008). It is possible that there were alternating periods of moist and dry conditions, and that plants were more common and/or more likely to be preserved during the wetter intervals.

Using other indicators. Many indicators including floral composition, mammal body size, numerous primates, and increased mammalian arborealism in the Green River Basin have suggested the peak mean annual temperatures in the Cenozoic were centered around the

Wasatchian/ Bridgerian boundary (Clyde et al., 1997; Alexander and Burger, 2001). The mean annual temperature of Lake Gosiute has been estimated to be 66.5 °F (19.2 °C) and the climate was likely similar to the Gulf Coast today (MAT 70 °F, Bradley, 1963).

Bridger A sediments south of Opal, WY preserve deltaic and fluvial sediments that interfinger with the Laney Member of the GRF (Pledge, 1969; McGrew and Sullivan, 1971).

Pledge (1969) documented at least 22 genera of mammals in this area with rodents and primates being the most common; however, turtles (mostly aquatic) and crocodiles were the most

abundant vertebrates. Crocodiles suggest at least warm temperate conditions and the presence of arboreal primates, aquatic turtles, and crocodiles indicate a widespread swamp (Pledge, 1969;

McGrew and Sullivan, 1971). Algae covered logs and primate fossils suggest a significant forest, whereas the presence of limestone deposits in the area indicate flat terrain with standing shallow water (McGrew and Sullivan, 1971). Bottom dwelling, shallow (<10 ft) freshwater gastropods of

Physa and Viviparus were observed; ostracods were also present in the lacustrine shales (Pledge,

1969). Red soils and laterites suggest warm temperate to subtropical conditions with seasonal rainfall (Pledge, 1969).

Part II: Local Geology and Depositional Environment at Blue Rim

Location of the Blue Rim Escarpment

The Blue Rim escarpment is approximately 20 miles north of Green River, WY (Figs. 1-

1, 1-2, 1-3). It is most easily accessed by traveling north on 191 out of Rock Springs, WY. Take a left on County Route 14 (after a sign about the Wild Horses). Continue on 14, passing underneath multiple sets of power lines. Take a slight right onto Blue Rim Road/5. Continue past the junction with 4 (about 2.5 miles after getting on 5). The first fossil sites are ~1 mile north of the junction with 4.

General Geologic Observations

Kistner (1973) studied the geology and paleontology of Bridger A in the Big Island-Blue

Rim area. He created multiple stratigraphic columns, including one (MS-6) in between the two more recent sections (Figs. 1-4, 1-5, 1-6), and mapped the geologic units. Although, Kistner

(1973) noted when he encountered fossils, including petrified wood, the paleobotany of the

Bridger Formation has been largely unexplored (Wilf et al., 1998b). A few taxa including reproductive material of an extinct sapindalean plant, Landeenia arailiodes, and sterile and fertile foliage of the climbing fern, Lygodium kaulfussi, have been described from Blue Rim

(Manchester and Zavada, 1987; Manchester and Hermsen, 2000). Woods have also been described from the Big Sandy Reservoir site elsewhere in the Bridger Formation (Boonchai and

Manchester, 2012); these are discussed more in Chapter 6. Wilf et al. (1998b) commented that the specimens at Blue Rim indicate minimal transport because floral remains are well-preserved and often intact, rather than fragmented. The fine-grained sediment also indicates a calm depositional environment (especially in the lower horizon), which suggests the leaves probably represented what was growing in an approximate 20 meter radius around each site (Wilf et al.,

1998b).

The surface material at Blue Rim displays popcorn weathering and strata are nearly horizontal. The outer layers of sediment that can be excavated by hand are very weathered and sloping. Dip measurements angled into the hill, regardless of which side of a badland finger the measurements were taken. A significant sized trench (backhoes necessary) would be needed to try to get accurate strike and dip measurements and to determine whether true cross beds were regularly present. However, the regional dip is small enough that it would not have a significant effect on measurements obtained for local stratigraphic sections (e.g., Figs. 1-4 and 1-5; M.E.

Smith, personal communication, July 2014).

The two stratigraphic sections (Figs. 1-4 and 1-5; Table A-1 and A-2) can be correlated to the work of Frank Kistner as his measured section 6 is situated between those done for this project which intercept the UF 19225 and UF 19297 plant localities (Fig. 1-7, Kistner, 1973).

Kistner’s unit 18, the lower blue layer, is equivalent to unit 3 in the UF 19297 section and the lower portion of unit 14 in my UF 19225 section. Kistner’s unit 19, a brown sandstone, corresponds to unit 4 in my UF 19297 section. Kistner’s (1973) unit 20, the upper blue layer, includes units 5 through 9 in the UF 19297 section and the upper part of unit 14 in the UF 19225

section. Kistner’s unit 25 coincides with unit 15 in the UF 19297 section and units 22-24

(combined in the strat section) of the UF 19225 section. Kistner’s (1973) unit 27 and 28 are likely correlative with units 16 and 17 in the UF 19297 section, respectively (Figs. 1-4 and 1-5,

Table A-1 and A-2).

Geologic Field Observations about Specific Quarries

UF 15761N (lower horizon). This quarry is composed of very friable non-calcareous, well-sorted siltstone, with some black (iron or manganese?) staining (to the left of Fig. 1-3A).

UF 18288 (lower horizon). This quarry has a well-sorted, homogenous, yellowish-gray matrix of very fine sand to silt. Sulfur and iron2 staining is present.

UF 19225 (lower horizon). Sediment matrix is gray, blocky, homogenous, well-sorted very fine sand. Numerous slickenslides are present along with sulfur2 and gypsum layers. An in situ silicified stump is present (23 cm in diameter, Fig. 1-3B, discussed in Chapter 6). Thousands of Lygodium leaf impressions are preserved.

UF 19296 (upper horizon). Fossils are not as numerous or as well-preserved as UF

19297. Lots of iron (alternatively manganese?) staining present; sulfur2 and gypsum deposits are present between layers. Some bedding planes, but rock is cracked, allowing ample opportunities for water to seep down. Matrix is light gray to light yellowish gray, well-sorted, homogenous, mostly silt, up to very fine sand in size. Leaves are scattered; this site is equivalent to units 22-24 in the UF 19225 stratigraphic section. The material from this quarry did not fizz with HCl; bivalves are present, some vertically oriented, apparently in situ.

2 Although no isotopic tests were performed, these rocks smelled sulfurous. High contents of iron sulfides including the minerals of pyrite, marcasite, and pyrrhotite have been found in fluvial, nearshore, and lacustrine sediments of the Green River and Wasatch Formations (Cole, 1975; Tuttle and Goldhaber, 1993).

UF 19297 (upper horizon). The leaf layer has lots of sulfur and iron (see footnote) staining and thin bands of organic matter. Some bands are mats of plant hash, whereas others preserve isolated, nicer specimens. Fossils are much less abundant than the lower horizon quarries. The fossils reside in a tannish to pinkish gray, well-sorted, homogenous, silt sized matrix that breaks in irregular blocks. There are layers of gypsum with sulfur (see footnote) and iron (alternatively manganese?). These deposits are concentrated together, and often fill cracks of joints in the matrix, suggesting that they are a secondary deposit that formed when mineral laden water traveled through weak layers in the rock (Fig. 1-3C).

UF 19404 (isolated channel fill). This site has more coarsely grained sediment and is stratigraphically older than the lower level quarries. A thinly laminated leaf mat is present with lots of layers of solid leaves. Below the leaf mat layer, a layer of moderately well-preserved, isolated leaves is present. Some sulfur and iron (see previous footnote) staining present. Grain size is very fine sand. No fizz occurred when exposed to HCl. Almost climbing ripples present; this feature suggests rapid, almost instantaneous deposition. Lots of muscovite is present. The depositional environment is hypothesized to be a crevasse splay (to get over levee) with a channel after (Fig. 1-3D).

Vertebrate Fossils at Blue Rim

Although the Bridger Formation is well-known for its vertebrate fauna, Blue Rim is not among the richest vertebrates sites. However, gar fish scales, pieces of turtle shell and leg bones, fish bone fragments (including a vertebra and a jaw fragment), and a crocodile vertebra were observed (Fig. 1-8). Kistner (1973) documented species of bony fish, reptiles, and mammals in his study area (including Blue Rim). The turtles formerly living in the Blue Rim area were soft shelled turtles (Family Trionychoidae) that lived in ponded environments (Paul Murphey, personal communication, July 2014). These turtles were often around 2 feet in diameter; their 49

shell was composed of different plates that had a dimpled surface and keratin on top (Paul

Murphey, personal communication, July 2014). Extant relatives of fossil trionychid turtles are aquatic, but nest on land (Plummer and Doody, 2010). Recent work has documented seven valid pan-trionychids species in the Bridger Formation (Vitek, 2012; Vitek and Joyce, 2015).

However, two species make up about 80% of all the turtles in the Bridger Formation (Paul

Murphey, personal communication, July 2014). Evidence for mammals in the area include a premolar from a small mammal in the Unit 4 to 5 area of the 2014 stratigraphic section (this may be a candidate site for screen washing) and a brontothere (herbivore, grazer) scapula piece (Paul

Murphey, personal communication, July 2014, Fig. 1-8B).

Invertebrate Fossils at Blue Rim

The strata at Blue Rim also preserve mollusks, specifically gastropods and bivalves (Fig.

1-9). Invertebrates have been found in various units of the stratigraphic sections (Figs. 1-4 and 1-

5) and in (at least) the following plant quarries: UF 15761N; 19225N; 19296; 19297; 19337.

Invertebrate fossils, especially bivalves, are more common in the upper leaf horizon as opposed to the lower. Elimia tenera (formerly Gonibasis tenera) is common in some stratigraphic units

(e.g., UF 19297 section units 8 & 16, Fig. 1-9A). This freshwater snail is most often found in shallow water (Hanley, 1974; Brand, 2007). The bivavles (e.g., Fig 1-9E-G) have similarities to the freshwater mussel family, Unionidae (Hanley, 1974). Occasional air breathing snails with similarities to the genera Oreohelix, Mesodon, and Biomphalaria (e.g., Fig. 1-9H) were also observed (Hanley, 1974).

Depositional Environment

Blue Rim preserves fluvial, partial lacustrine, and total lacustrine environments (M.E.

Smith, personal communication, July 2014).

Blue layer. The bluish green layers in the Bridger Formation (studied in the upper

Bridger) are often representative of the diagenetic alteration of potassium rich volcanic matter

(carried in fluvially) to the clay celadonite (Emmett Evanoff, personal communication, Feb.

2013). This clay, ranging from green to blue to turquoise is a phyllosilicate in the mica group

(Wise and Eugster, 1964). This rapidly deposited material often contains minerals that can be radiometrically dated (see below). In the Bridger, this material is usually sourced from the

Absaroka volcanic field in northwestern Wyoming, whereas the actual ashes (crystal rich and more felsic) are from the Challis volcanic field in Idaho (Emmett Evanoff, personal communication, Feb. 2013).

Lakes and ostracods. Ostracods are a freshwater indicator; they can only tolerate slight salinity. The presence of ostracods in a unit at Blue Rim suggests a lacustrine environment, possibly a tongue of the Laney Member of the GRF. For example, the main blue layer above the

UF 15761S quarry is likely lacustrine, protodeltaic with possible turbadites (represented by the discontinuous reddish brown sandstones). Some laminations are present, but it appears to be bioturbated to such an extent that it is massive (M.E. Smith, personal communication, July

2014). The base of this unit has white layers of papers shales with ostracods, suggesting deeper water in a freshwater lake. These shales are composed of kerogen rich calcium, specifically a micrite. The plants in the UF 15761 quarries were likely growing along a lacustrine shoreline. As the lake was transgressing, plants were expanding over the adjacent floodplain. In general, continuous sandstones in the Blue Rim area are representative of lacustrine shorelines (M.E.

Smith, personal communication, July 2014). The continuous sandstone with ostracods and some cross beds near the top of the Blue Rim escarpment is also representative of a lacustrine phase.

This transitions to a higher energy muddy beach as the lake regresses again. Units that fizz with

exposure to HCl are also often representative of lacustrine environments (M.E. Smith, personal communication, July 2014).

Fluvial, deltaic, and floodplain. Channel/discontinuous sandstones suggest ancient rivers with adjacent floodplains. Low relief deltas leading into the lake were present. Evidence for the presence of deltas is provided by the different thickenings of the units (M.E. Smith, personal communication, July 2014). Small ponds around the edge of Lake Gosiute are also present at Blue Rim; for example, stromatolites were observed near the base of the Blue Rim escarpment north of the UF 19297 stratigraphic section (Paul Murphey, personal communication,

July 2014).

Radiometric Ages

Previous workers (e.g., Kistner, 1973; Brand, 2007) thought that all the non-lacustrine sediments in the Blue Rim area were representative of Bridger A. However, new radiometric dates indicate some younger material is present at the top of the escarpment and that more time is represented in the section than previously thought.

Reworked ashes were sampled (in 2014) from the prominent blue-green marker unit and from two sand beds near the top of the Blue Rim escarpment for 40Ar/39Ar geochronology.

Sanidine phenocrysts were separated via crushing, leaching in dilute HCl and HF, and hand- picked under refractive index oils. Sanidine crystals from studied ash beds were irradiated together with sanidine from the Fish Canyon tuff (FCs) in the TRIGA reactor at Oregon State

University in cadmium shielding. Single sanidine crystals were fused using a 25W CO2 laser and analyzed for Ar isotopic composition using a MAP 215-50 gas source mass spectrometer at the

University of Wisconsin-Madison WiscAr laboratory. Weighted mean ages for ash beds and ignimbrites were calculated relative to the 28.201 Ma age for the Fish Canyon sanidine (FCs,

Kuiper et al., 2008), and are reported in Table 1-1 with both 2σ analytical (sample plus J 52

uncertainty) uncertainties, and full (analytical, decay constant and intercalibration) uncertainties.

Outliers were excluded from the weighted mean when their inclusion resulted in an MSWD

(mean square of weighted deviates) that exceeded the Student’s-t test criteria. Complete results are documented in Fig. A-1.

A coherent population of young grains within the base and middle of the blue-green marker is consistent with pumice clasts and euhedral biotite grains in indicating deposition of juvenile volcanic material mixed with a minor detrital component following a major eruption in the Challis volcanic field at ~49.3 Ma (Fig. 1-10). Two sand beds sampled near the top of the rim yielded more detrital grains, but six young grains exhibit a coherent population that gives a weighted mean age of ~48.3 Ma (Fig. 1-10). These results indicate that the blue-green marker is temporally equivalent to Bridger A/1b, but the uppermost part of the Blue Rim escarpment is time equivalent to Bridger C or D/3. These new dates are placed into the context of other radiometric dates from the Green River and Bridger Formations and correlated to both magnetostratigraphic and biostratigraphic divisions in the early to middle Eocene in Fig. 1-11.

Specifically, BR-3, with an estimated age of 48.98 ± 0.38 Ma was collected at the base of the main blue layer, just above the UF 15761S plant quarry (elevation 6737 ft). Sample BR-4 was collected from the lower main blue layer in the 2014/UF 19297 stratigraphic section (Fig. 1-

5, elevation 6745 ft) and resolved an estimated age of 49.43 ± 0.23 Ma. Because these two samples were collected from the same stratigraphic unit, they were combined for an age of 49.29

± 0.18 Ma (Table 1-1, Fig. 1-10). Sample BR-6 was collected from the very top of the 2014/UF

19297 stratigraphic section (unit 17, Fig. 1-5) and resolved as 48.29 ± 0.45 Ma (elevation 6861 ft; Table 1-1, Fig. 1-10, Fig. A-1).

Based on this information, the lower leaf horizon (which includes most of the reproductive material) is definitely Bridger A/1b. However, sample BR-6 from the very top of the escarpment (above all plant fossils) and just below the non-Eocene material, resolved as

Bridger C or D/3. This suggests much slower sediment accumulation than the basin average and may represent a gradual slowdown, one, or many hiatuses in deposition (M.E. Smith, personal communication; Smith et al., 2008). In general, the rate of deposition can be estimated by measuring the thickness between dated beds and then accounting for lacustrine deposition; volcanioclastics are deposited quickly and typically lack fossils (Paul Murphey, personal communication, July 2014). It remains unclear whether the upper leaf level is Bridger A/1b or if it is younger. The prominent lacustrine marker near the top of the Blue Rim section could be representative of the Lyman Limestone between Bridger A/1b and B/2 (Murphey et al., 2001;

Brand, 2007; Murphey and Evanoff, 2011; Murphey et al., 2011). The gastropod

Goniobasis/Elimia is prominent just above this unit in the UF 19297 stratigraphic section (Fig.1-

5) and there is a known Goniobasis marker bed between Bridger A and B (Paul Murphey, personal communication, July 2014). Goniobasis is found in lake shore (littoral lacustrine) environments (Hanley, 1974, 1976) so this would support the regression of Lake Gosiute

(represented by the Lyman Limestone below) with shallower water just above this unit. Blue

Rim is placed in the context of our understanding of the lakes of the Green River Formation at

~49 Ma in Fig. 1-12. Paleorivers were depositing reworked volcanic sediment from the Absaroka complex in the Bridger Formation before meeting the remnants of Lake Gosiute to the southeast of Blue Rim (Fig. 1-12).

Part III: Dissertation Overview

Overarching Research Questions

1. How does the Blue Rim flora contribute to our understanding of plant species in the latest Early Eocene?  1a. Are new species present? If so, what is their biogeographic history?  1b. Is there evidence of an expanded range of taxa known in the regional flora or from other Eocene localities?  1c. Are there taxa we expected to find at Blue Rim that have not been recovered?

2. What paleoclimate is indicated by the flora?  2a. To what extent did the local climate change through the interval of deposition at Blue Rim?  2b. How do these results compare to the regional climate estimates from the latest Early Eocene? What changed since the PETM?

Overview of the Following Chapters

Chapter 2: Leaf fossils from Blue Rim. The most prevalent macrofossils at Blue Rim are leaves. Leaf fossils were examined from all Blue Rim quarries and morphotyped within each stratigraphic horizon. The isolated channel fill quarry (UF 19404), which is stratigraphically older than either of the other two horizons, was treated independently. However, all lower horizon quarries and all upper horizon quarries were studied together. The quarries from each of the two main stratigraphic horizons were combined because diversity was low at individual quarries and by lumping them together, it was easier to reach the minimum number of morphotypes required for a paleoclimate analysis. In each case, the leaves were grouped into morphotypes and described using the Manual of Leaf Architecture (Ellis et al., 2009). When possible, morphotypes were assigned taxonomic identifications, usually from similar specimens from other localities already described in the literature. Although many of these taxonomic identifications may not conform to our current understanding of that clade, the names were still provided to indicate that the Blue Rim specimens were the same species as specimens found in

other localities. Morphotypes are described, discussed where applicable, and figured. All related paleoclimate and paleoecological analyses are in Chapter 7.

Chapter 3: Reproductive structures: macrofossils and dispersed palynoflora.

Reproductive macrofossils (flowers, fruits, and seeds) from all quarries at Blue Rim were morphotyped. Frequently, a reproductive structure was only found at one or a few nearby quarries. Furthermore, the main lower horizon (including quarries of UF 15761 and UF 19225) produced a significantly higher diversity of reproductive structures than the upper horizon

(including quarries of UF 19297 and UF 19296) and only a few reproductive structures were common to both horizons. Morphotypes were described and figured. If specimens matched others already documented in the literature, this was noted. Otherwise, potential taxonomic assignments were discussed if there were enough characters for a hypothesis. One of the flower morphotypes is representative of a new species in the tribe Homalieae (Salicaceae) and is likely associated with previously unidentified leaves.

Well-preserved fossil pollen and spores were recovered from more stratigraphic units than the macrofossils. Three of the 12 units investigated (out of ~26) had good to excellent recovery from the 2012/UF 19225 locality stratigraphic section. All 17 units of the 2014/UF

19297 stratigraphic section were processed for dispersed pollen and spores with 5 of these having good to excellent recovery. The isolated channel fill locality, UF 19404, also had excellent pollen recovery. The pollen and spores in select units were photographed, morphotyped, and assigned to tentative taxonomic groups when possible. Within the dispersed palynoflora, angiosperms are dominant, but conifers including pines are common. The taxonomic composition of the microflora seems to be representative of both the regional and local flora.

Chapter 4: Fossil palm flowers from the Eocene of the Rocky Mountain region with affinities to Phoenix L. (Arecaceae: Coryphoideae). Numerous trimerous fossil flowers have been collected from Eocene strata in Wyoming, Utah, and Colorado. While many specimens have been assigned tentatively to Arecaceae, they have not been described formally, and their systematic placement within this large family has not been determined. Fossils from the Eocene

Bridger, Green River, and Wind River Formations were photographed, described, and measured.

Pollen extracted from a stamen was studied by transmitted light, epifluorescence, and scanning electron microscopy. The floral and pollen morphological characters were compared to extant and fossil genera of angiosperms with a focus on Arecaceae. Both macromorphological and palynological characters agree with assignment of the fossils to the extant genus Phoenix (L.).

This is significant because Phoenix is native to Africa and southeast Asia today, but these fossils indicate a much broader distribution in the past. In addition, Phoenix cannot tolerate extensive freezing conditions, indicating a mostly frost-free climate when it was growing in the Rocky

Mountain region during the Eocene. These fossil flowers represent a new species, Phoenix windmillis S.E. Allen sp. nov., significant because it is the first confirmation of the genus in the

North American fossil record. The absence of pinnate induplicate palm leaves in the Eocene of

North America that could be interpreted as Phoenix demonstrates the need to examine dispersed reproductive organs, as well as leaves, in evaluating fossil floras.

Chapter 5: Icacinaceae from the Eocene of western North America. The Icacinaceae are a pantropical family of trees, shrubs, and climbers with an extensive Paleogene fossil record.

Our improved understanding of phylogenetic relationships within the family provides an excellent context for investigating new fossil fruit and leaf material from the Eocene of western

North America. Fossils from early and middle Eocene sediments of western Wyoming (including

Blue Rim), northeastern Utah, northwestern Colorado, and Oregon were examined and compared to extant species of Iodes and other icacinaceous genera as well as previously described fossils of the family. Three new fossil species are described, including two based on endocarps (Iodes occidentalis sp. nov. and Icacinicaryites lottii sp. nov.) and one based on leaves (Goweria bluerimensis sp. nov.). The co-occurrence of I. occidentalis and G.bluerimensis at Blue Rim suggests these might represent detached organs of a single species. A new genus,

Biceratocarpum, was also established for morphologically distinct fossil fruits of Icacinaceae previously placed in Carpolithus. However it has since been found that this material is more appropriately assigned to the extant genus Iodes (Stull et al., 2016). Biceratocarpum brownii gen.et comb. nov. resembles the London Clay species “Iodes” corniculata because it possesses a pair of subapical protrusions. These fossils increase our knowledge of Icacinaceae in the

Paleogene of North America and highlight the importance of the Northern Hemisphere in the early diversification of the family. They also document interchange with the Eocene flora of

Europe and biogeographic connections with modern floras of Africa and Asia, where Icacinaceae are diverse today. The present-day restriction of this family to tropical regions offers ecological implications for the Eocene floras in which they occur.

Chapter 6: Reconstructing the local vegetation and seasonality of the lower Eocene

Blue Rim site of southwestern Wyoming using fossil wood. The wood specimens from Blue

Rim were cut and prepared for anatomical study with transverse, tangential, and radial sections.

These were examined and described using the IAWA’s guidebooks (Wheeler et al., 1989;

Richter et al., 2004) and then grouped into morphotypes. Morphotype characters were searched on InsideWood (InsideWood, 2004-onwards; Wheeler, 2011) and matches were reviewed for similarities and differences to the unknown fossil specimens. Once a hypothesis for a potential

taxonomic identification was developed, the literature about that clade was explored in detail.

One gymnosperm wood was discovered along with at least three angiosperm types. Stumps with complete diameters were also used to estimate tree height. Methods to estimate specific gravity and vulnerability index were applied when possible.

Chapter 7: Floral overview, paleoclimate, and paleoecology of Blue Rim with a comparision to other early Eocene sites from western North America. This final chapter synthesizes the taxonomic composition and diversity of the Blue Rim flora with a complete look at all plant organs and tissues. Methods to estimate past temperature and precipitation from plants including leaf physiognomic approaches are introduced and applied to the Blue Rim flora when applicable. Results from paleoecological methods, including leaf mass per area, are also presented. Both the taxonomic and paleoclimate results from the Blue Rim flora are placed in the broader context of the early Eocene, followed by a comparison to other early Eocene floras from western North America.

Appendices. Appendices are included with some chapters. These provide extra information or descriptions of select individual specimens, as opposed to the morphotype descriptions included within the chapters.

Table 1-1. Summary of single crystal sanidine 40Ar/39Ar analyses: Bridger Formation, Blue Rim, WY. Sample, location, Latitude Longitude n MSWD Weighted ± 2 † ± 2 ‡ material mean age (Ma) BR-6, upper BR, ± ± 41.8213° N 109.5949° W 6 of 18 0.93 48.29 sandstone 0.45 0.48 BR-5, upper BR, 41.8210° N 109.5952° W 0 of 19 detrital n.a. sandstone BR-4, pumiceous ± ± sandstone, Blue-green 41.8218° N 109.5972° W 9 of 20 0.24 49.43 0.23 0.28 marker BR-3, basal sandstone, 18 of ± ± 41.7987° N 109.5834° W 1.20 48.98 Blue-green marker 20 0.38 0.41 Blue-green marker 27 of ± ± 1.08 49.29 composite 40 0.18 0.24 Notes. All ages calculated relative to the 28.201 Ma age for FCs using the equations of Kuiper et al. (2008) and Renne et al. (1998), using the decay constants of Min et al. (2000), and are shown with 2σ analytical and fully propagated uncertainties, which incorporate decay constant and intercalibration uncertainties. Neutron flux monitor: FCs-Fish Canyon Tuff sanidine, Cf. Table 2 for analytical details. BR-6 and the Blue-green marker composite ages reflect interpreted depositional ages. †Analytical uncertainty. ‡Fully propagated uncertainty.

Figure 1-1. Map indicating location of Blue Rim in Sweetwater County, southwestern, Wyoming. Major highways indicated in red.

Figure 1-2. The Blue Rim escarpment in Sweetwater County, WY. A) View looking north (standing south of all plant localities). B) Unit 8 of the UF 19225 strat section, looking up section with scattered petrified wood. C)View looking south (standing north of all plant localities). D) Concretions in unit 9 of the UF 19297 strat section. E) View of the escarpment from near the base of the UF 19297 strat section. Highest point is 115 °E. F) Area providing evidence for the combination of units 22-24 in UF 19225 strat section.

Figure 1-3. Select Blue Rim plant quarries. A) UF 15761S with (L-R) Greg Stull, Jim Barkley, and Steve Manchester. B) In situ wood preserved in the UF 19225 quarry. C) Overview of the UF 19297 quarry area. D) The isolated channel fill, UF 19404, near the base of the escarpment. Photo by S.R. Manchester. E) Units 22-24 in the UF 19225 strat section. The UF 19296 plant quarry is nearby.

Figure 1-4. Stratigraphic section including plant locality UF 19225.

Figure 1-5. Stratigraphic section including plant locality UF 19297.

Figure 1-6. Estimated correlation of the two stratigraphic sections.

Figure 1-7. Overview of topography of Blue Rim escarpment showing the approximate locations of the recent stratigraphic sections and one of Frank Kistner in the same area (1973). Map equivalent to a USGS 1:24,000 scale. Base map view from BaseCamp software included with Garmin TOPO! 2009 North Central U.S. digital topographic map.

Figure 1-8. Scattered vertebrate and petrified wood fragments at Blue Rim. A) Turtle shell fragment in unit 4 of the UF 19297 strat section. B) Brontothere scapula just above the UF 19297 plant locality. Identification by Paul Murphey. C) Unidentified bone fragment. D) Scattered pieces of petrified wood just to the north of the UF 19297 quarry. Scale bars in 1 cm increments.

Figure 1-9. Invertebrate fossils at Blue Rim. A) Elimia tenera (formerly Goniobasis tenera) in unit 8 of the UF 19297 strat section. Scale bar increment = 1 cm. B-D) Unidentified mollusks preserved in the UF 19225N quarry. E-G) Bivalves from UF 19297. H) Gastropod from UF 15761N. Scale bar increments B-G = 1 mm.

Figure 1-10. 40Ar/39Ar geochronology: A) Relative probability plots of Eocene-aged sanidine from the volcaniclastic-lacustrine blue-green marker and an overlying pumice-bearing volcaniclastic sandstone (sample BR-6); B) Relative probability plot of 40Ar/39Ar ages for detrital feldspar grains from the middle and upper Blue Rim, showing Phanerozoic and late Paleozoic ages characteristic of the Idaho paleoriver (cf. Chetel et al., 2011). Figure created by M.E. Smith, Northern Arizona University.

Figure 1-11. New 40Ar/39Ar ages for Blue Rim in the context of existing 40Ar/39Ar, biostratigraphic, and magnetostratigraphic age framework for the Green River and Bridger Formations (cf. Smith et al., 2008; Smith et al., 2010). Ash beds: BG = blue- green marker; uBR = upper Blue Rim; W = Willwood ash; S = Scheggs tuff; F = Firehole tuff; B = Boar tuff; G = Grey tuff; M = Main tuff; L = Layered tuff; 6 = 6th tuff; A = Analcite tuff; An = Antelope sandstone; CB = Church Butte tuff; HF = Henrys Fork tuff; SC = Sage Creek ash. Figure created by M.E. Smith, Northern Arizona University. 71

Figure 1-12. Shaded relief map of the North American Cordillera showing the paleogeographic position of the Blue Rim (BR) relative to major paleorivers, lake basins, and tectonic elements. EC refers to early Bridgerian Elderberry Canyon local fauna of Emry (1990). Core complexes occur near the Cordilleran paleodivide: B – Bitterroot; A – Anaconda; W – Wildhorse; G – Albion-Raft River-Grouse Creek; S – Snake. Note that the Bridger Formation at Blue Rim represents the topsets of the Sand Butte delta (cf. Smith et al., 2008). Paleorivers summarized from Henry et al. (2012), Dickinson et al. (2012) and Chetel et al. (2011). Figure created by M.E. Smith, Northern Arizona University.

CHAPTER 2 LEAF FOSSILS FROM BLUE RIM

Leaves are preserved in two main stratigraphic horizons at Blue Rim and from an isolated channel fill. They are morphotyped and described here starting with the oldest stratigraphic layer moving to the youngest. The leaves from the isolated channel fill (locality UF 19404, stratigraphically oldest) are described first in Part I, followed by those from the lower horizon

(multiple localities) in Part II, and the upper horizon in Part III. The stratigraphic framework and geologic context of these localities and horizons was discussed in the previous chapter (Chapter

1).

Specimens were described following the terminology in the Manual of Leaf Architecture

(Ellis et al., 2009). Comparisons to extant taxa were often done by examining leaves in online cleared leaf databases (http://peabody.research.yale.edu/nclc/ ; http://clearedleavesdb.org/; http://ucmpdb.berkeley.edu/photos/cleared_leaf.html ). When possible, morphotypes were matched to fossil taxa already recognized in the literature. In these cases, the species name is listed after the morphotype assignment. Only a handful of the fossil leaf morphotypes have been assigned to extant genera. Leaves of many taxa have convergent morphology, even in unrelated clades. Furthermore, many of the fossil taxa that are aligned with an extant family, do not match any extant species and are likely representative of extinct taxa. In these cases, it is not appropriate to assign leaves to a modern genus even though that is the approach other authors have taken (e.g., MacGinitie, 1969; MacGinitie, 1974).

Each part (I, II, & III) has a separate morphotype designation system so taxa can be compared and contrasted between all stratigraphic horizons at Blue Rim. Hence, some of the morphotypes from different strata are representative of the same species even if they have a different morphotype designation. The hypothesized overlap among these designations (i.e., the

floristic similarity among units) is discussed in the conclusion to this chapter. This approach is slightly different to the work of others (e.g., Johnson, 1989; Peppe et al., 2008) who consecutively numbered specimens from a region or time period and then assigned them to morphological groups called operational taxonomic units to address diversity or climate questions. Morphotypes were created independently within each horizon at Blue Rim because the horizons are separated by extensive gaps in time (e.g., the lower horizon and upper horizon may be as much as 1 million years apart) and the lithology is different. Both the isolated channel fill and the upper horizon are likely representative of allochthonous floras based on the higher diversity of leaves, lower preservational quality, fewer small reproductive structures, and coarser sediment. In contrast, the lower horizon is likely representative of a more autochthonous, local flora. The leaves are usually well preserved and more frequently intact, indicating a shorter transport distance. Furthermore, delicate flowers with in situ pollen are preserved in the lower horizon and the sediment is more fine-grained.

Many of the specimens have informal field census numbers or letter abbreviations listed in parenthesis after the formal number. These comments are not comprehensive, but were included when available. Abbreviations following the specimen numbers include:

 # = field census number  ? = best guess for morphotype placement/taxonomic assignment, but not fully confident  c = evidence of compound leaf  f = fragment  HOV pp = Higher order venation poorly preserved  HOV wp = Higher order venation well preserved  ls = large specimen (large example of this morphotype)  nc = not censused  nm = no margin preserved  p = petiole present  pp = poorly preserved  ss = small specimen (small example of this morphotype)

Part I: Leaves from the Isolated Channel Fill UF 19404

Toothed Laminae

Morphotype—Toothed 1 (Figs. 2-1A-F).

Species—Macginitiea wyomingensis (Knowlton and Cockerell) Manchester

Specimens—UF 19404-61691 (173), 61694 (nc), 61696 (nc), 61706 (24), 61718 (10).

Description—Leaves mesophyllous (19404-61706) to larger (all specimens fragmentary).

Incomplete length and width on three specimens: 11.7 cm by 11.7 cm (19404-61706), ~10 cm by

12 cm (19404-61694), ~9 cm by 11 cm (19404-61696). Elliptic to obovate in shape. Symmetry could not be determined. Palmately lobed (3 lobes—19404-61706; 5 lobes—19404-61691,

61694, 61696). Specimens occasionally and irregularly toothed on some lobes. Apex acute, base characters not preserved (19404-61706). Complete base or apex not present on any specimen.

Primary venation palinactinodromous; primaries over 1 mm wide (19404-61706).

Secondaries brochidodromous to semicraspedodromous. Interior secondaries present. Marginal secondary present. Major secondaries slightly irregular in spacing. Secondaries with excurrent attachment to midvein. Intersecondaries present; perpendicular to midvein, variable in length, distal course perpendicular to subjacent major secondary, less than one per intercostal area.

Tertiaries alternate percurrent (where visible). Higher order venation likely reticulate.

Teeth irregular with one order. When present, ~2 teeth per cm (19404-61696, 61718).

Sinuses rounded, tooth shape CC/CV to CC/RT.

Discussion—Macginitiea wyomingensis (Platanaceae) is also found in the upper horizon at Blue

Rim, at Kisinger Lakes (northwestern Wyoming), and in the Green River Formation

(MacGinitie, 1969; MacGinitie, 1974; Manchester, 1986; Johnson and Plumb, 1995).

Morphotype—Toothed 2 (Figs. 2-2A-B).

Specimen—UF 19404-61691 (172).

Description—Lamina fragment notophyllous; base and apex missing. Margin serrate. Venation pinnate, primary vein thick (>1 mm in diameter). Secondaries craspedodromous to semicraspedodromous (margin partially obscured for most of lamina). Proximal branches off many secondaries present. Secondaries closely and regularly spaced with a uniform angle (~70°) to the midvein. Secondaries with excurrent attachment to the midvein. Intersecondaries present, generally parallel to secondaries, but some with a more irregular course. Intersecondary length variable, some with a reticulating/ramifying distal course. At least one intersecondary per intercostal area. Tertiaries not well-preserved, appearing quite irregular (many as branches of lower gauge off secondaries).

Teeth with angular sinuses, possibly more than one order. Shape ~CV/CV; principal vein present, entering the tooth submedially.

Discussion—This lamina has strong similarities to the leaflets of Rhus L. and some other genera of Anacardiaceae. The feature of percurrent tertiary veins that weaken in the middle of the intercostal area is a diagnostic feature for Anacardiaceae.

Morphotype—Toothed 3 (Figs. 2-3A-B).

Specimen—UF 19404-61723 (27).

Description—Marginally attached lamina fragment, microphyllous. Base asymmetrical in width.

Margin serrate to crenate. Apex absent; base acute, cuneate. Primary venation pinnate; secondaries likely semicraspedodromous, but little intact margin preserved. Secondaries with slightly irregular spacing; angle of divergence from the primary slightly different on either side of the primary in the lower half of the lamina. Secondaries with excurrent attachment. Higher order venation not preserved.

Teeth regularly spaced where present, 3-4 per centimeter. Possibly two orders of teeth; sinuses angular. Tooth shape variable from CV/CT to almost ST/ST.

Discussion—This asymmetrical lamina can be distinguished from other toothed types present in the UF 19404 locality by its straight, acute base and stout primary. It also has small, appressed teeth.

Morphotype—Toothed 4 (Figs. 2-4A-C).

Specimens—UF 19404-61671 (nc, darker lamina), 61686 (1).

Description—Leaves microphyllous to notophyllous. Apex not preserved; base obtuse. Margin toothed (serrate). Primary venation pinnate. Secondaries semicraspedodromous with decurrent to mostly excurrent attachment. Secondaries regularly spaced and angled where visible (~45-55°, mid-lamina, basal secondaries diverge at ~65° off the primary; specimen UF 19404-61671).

Tertiaries mixed percurrent. Higher order venation not preserved.

One order of regularly spaced teeth present. Four to five teeth per centimeter; sinuses angular. Tooth shape variable, often CV/CV with pointed apices.

Discussion—This morphotype matches the DE type found in the upper horizon at Blue Rim.

Morphotype—Toothed 5 (Figs. 2-5A-C).

Specimens—UF 19404-61715 (68), 61716 (151).

Description—Leaves notophyllous to mesophyllous. Shape likely elliptic; symmetry could not be determined. Leaves unlobed and toothed (serrate and crenate). Primary venation pinnate; secondaries semicraspedodromous. Secondaries evenly spaced and angled (~60-70°) with excurrent attachment to rarely decurrent attachment to the midvein. Intersecondaries present— parallel to major secondaries, distal course parallel to major secondaries, less than one per

intercostal area. Tertiaries mixed percurrent (opposite more common). Higher order venation irregular reticulate.

One order of regularly spaced teeth preserved. Teeth small, 4-5 per centimeter. Sinuses slightly angular to rounded. Tooth shape CV/CV with some variability to ST/ST with rounded apices.

Discussion—The small, closely spaced, rounded teeth can be used to help distinguish this morphotype from others found in the UF 19404 quarry.

Morphotype—Toothed 6 (Figs. 2-6A-C).

Species— cf. Populus cinnamomoides (Lesquereux) MacGinitie

Specimen—UF 19404-61693 (nc).

Description—Marginally attached petiolate leaf, notophyllous. Slightly incomplete leaf 10 cm long, slightly incomplete width 4.2 cm for a length to width ratio of 2.4:1. Lamina elliptic, but close to ovate. Medial and basal symmetry could not be determined. Leaf unlobed and toothed.

Apex acute and likely straight, but not completely intact. Base acute and approximately straight.

Primary venation pinnate, although basal secondaries are just shy of being considered primaries.

Agrophics present, simple. Major and minor secondaries semicraspedodromous. Fimbrial vein present. Secondary spacing abruptly increasing proximally with one pair of acute basal secondaries. Secondaries with excurrent attachment to the midvein. Possible intersecondaries, they cannot be distinguished from tertiaries. Tertiaries mixed percurrent with an acute to almost perpendicular angle to the midvein. Higher order venation appears reticulate.

One or two orders of regularly spaced teeth present where visible. Approximately three teeth per centimeter with angular sinuses. Tooth shape CV/CV to ST/CV. Principal vein present,

terminating between the apex and the distal flank of the tooth. Tooth apex with a gland of dark tissue at the termination of the principle vein.

Discussion—This specimen appears to have salicoid teeth and its characters are in agreement with Populus specimens from other quarries at Blue Rim.

Morphotype—Toothed 7 (Figs. 2-7A-B).

Specimen—UF 19404-61663 (nc).

Description—Microphyllous, toothed lamina fragment. Apex acute and straight; base not preserved. Primary venation pinnate; secondaries craspedodromous. Secondaries regularly spaced and angled where preserved. Secondaries with excurrent attachment to midvein.

Secondaries depart midvein at ~90° and slowly bend upward starting at the midvein to terminate in a tooth. Possible rare intersecondaries. Tertiaries mixed percurrent. Tertiaries with obtuse angle to midvein. Higher order venation not preserved due to coarse sediment.

One order of regularly spaced teeth present with 3-4 teeth per centimeter. Sinuses angular. Tooth shape variable from CC/CV to ST/CV to CV/CV. Principle vein present, entering the tooth submedially, appears to terminate at the tooth apex.

Discussion—This specimen has some similarities, including one tooth per secondary vein, the secondary veins entering each tooth submedially, the right-angle to obtuse shape of the teeth, and closely spaced percurrent tertiaries, to Cedrelospermum nervosum (Newberry) Manchester

(Ulmaceae) from the Green River Formation of Utah and Colorado (Manchester, 1989).

However, it cannot be assigned due to the lack of a complete leaf and the winged fruits, known from complete specimens of the Green River Formation, have not been found at this site.

Morphotype—Toothed 8 (Fig. 2-8A).

Specimen—UF 19404-61675 (nc).

Description—Notophyllous, toothed lamina fragment. Apex likely obtuse and rounded, but only partially preserved. Base not preserved. Agrophic venation present. Tertiaries opposite percurrent where visible. Other venation characters not preserved.

Teeth not well-preserved, but where visible—CV/CV in shape with rounded apices and angular sinuses. Principle vein present with marginal termination.

Discussion—This leaf type with its acrodromous venation, agrophic veins, and blunt teeth, although incomplete, has similarities to extant leaves of Rhamnaceae (e.g., Ceanothus L.).

Morphotype—Toothed 9 (Figs. 2-9A-B).

Specimen—UF 19404-61660 (nc).

Description—Incomplete lamina at least mesophyllous. Margin toothed; apex and base missing.

Secondaries semicraspedodromous with excurrent attachment to the midvein. Tertiaries mixed percurrent, mostly opposite. Tertiaries with an obtuse angle to the primary. Higher order venation irregular reticulate where visible.

Two to four teeth present per centimeter; teeth seemingly somewhat irregularly spaced, but only visible in a small portion of the lamina. Sinuses appearing angular; tooth shape could not be determined.

Discussion—This leaf type appears likely to have been palmately or palinactinodromously lobed, based on the divergence angle of the two primary veins seen in the lamina of Fig. 2-9A. It might have been part of a large Macginitiea leaf, but it is too fragmentary to verify if lobes were indeed present, and the total number of primary veins is not certain, but probably at least three, based on the symmetry.

Morphotype—Toothed 10 (Fig. 2-10A).

Specimen—UF 19404-61702 (80?).

Description—Marginally attached lamina, microphyllous. Length 7.6 cm, squished width 1.8 cm for an approximate length to width ratio of 4.2:1. Shape appears ovate. Lamina unlobed and toothed. Apex very acute and straight to acuminate. Base convex where visible. Primary venation pinnate. Secondaries very faint, but either craspedodromous or semicraspedodromous. Details of higher order venation not preserved.

Teeth regularly spaced in lower portion of lamina, not present in narrow apex. One order of teeth present with 2-3 teeth per centimeter. Sinuses angular. Teeth ST/ST to ST/CV in shape.

Discussion—This leaf type can be distinguished from the other toothed morphotypes from the

UF 19404 locality by its overall shape, long narrow apex, and ST/ST teeth. The proximal flanks of the teeth are much longer than the distal flanks.

Morphotype—Toothed 11 (Fig. 2-11A).

Specimen—UF 19404-61717 (178).

Description—Microphyllous fragment. Margin most likely toothed. Neither apex nor base preserved. Primary venation most likely pinnate; secondaries appear semicraspedodromous with excurrent attachment to the midvein. Intersecondaries present; perpendicular to midvein, appear shorter than the subjacent secondary, distal course of intersecondary perpendicular to subjacent major secondary, less than one per intercostal area. Tertiaries mixed percurrent with an obtuse angle to the primary. Quaternary and quinternary vein fabric irregular reticulate. Areoles present with good development. Possible tooth shape CV/CV.

Discussion—The basal half of this lamina is missing, but it might represent the distal part of a

Macginitiea lobe.

Morphotype—Toothed 12 (Fig. 2-12A).

Species—Serjania rara MacGinitie

Specimen—UF 19404-61709 (73).

Description—Marginally attached, microphyllous lamina. Length 4.1 cm, width 2.1 cm for a length to width ratio of 1.95:1. Laminar shape elliptic; medially and basally slightly asymmetric.

Lamina unlobed and crenate. Apex acute and straight to slightly convex; base acute and straight.

Primary venation pinnate; secondaries likely craspedodromous, but very poorly preserved.

Higher order venation not preserved.

Teeth irregularly spaced; teeth rounded, CV/CV. One tooth has a concentration of pigmented tissue at its apex, possibly indicating glandularity, but teeth not spinose.

Discussion—Serjania rara is also found at Kisinger Lakes (MacGinitie, 1974) and in the other two leaf horizons at Blue Rim.

Morphotype—Toothed 13 (Figs. 2-13A-C).

Species—“Aleurites” fremontensis (Berry) MacGinitie

Specimens—UF 19404-61676 (nc), 61685 (194), 69291 (121).

Description—Leaves petiolate, marginally attached (petiole over 1.5 mm wide on specimen

19404-61685). Fragments notophyllous. Margin untoothed near base, but toothed in rest of lamina. Base symmetrical; medial symmetry not determined. Apex not preserved; base obtuse to acute and cuneate. Primary venation pinnate or palinactinodromous. Naked basal veins present; five to seven basal veins. Secondaries with excurrent attachment to the midvein. Other venation characters not preserved.

Discussion—Although all of these specimens are fragments, they are assigned to what

MacGinitie (1974) called “Aleurites” fremontensis based on the following characters: generally symmetrical about the midvein, an entire base (toothed areas in rest of leaf not well-preserved in these specimens), secondaries arising at opposite or subopposite locations, thinner intramarginal,

but prominent secondary vein along the margin in the basal portion of the leaf, stout petiole, and lamina surface covered with pigmented dots. “Aleurites” fremontensis is also found at the

Kisinger Lakes sites in northwestern Wyoming in addition to the lower horizon at Blue Rim.

Morphotype—Toothed 14 (Fig. 2-14A-B).

Specimen—UF 19404-61676 (nc).

Description—Lamina microphyllous, marginally attached. Incomplete length 4 cm, width 1.2 cm for a length to width ratio of 3.3:1. Lamina medially symmetric, base symmetry cannot be determined. Lamina unlobed and toothed. Apex and base likely acute. Primary venation pinnate; no higher order venation preserved.

Teeth appear to be regularly spaced. One order of three to four teeth per centimeter.

Teeth with blunt, non-spiny apices. Tooth shape not well-preserved, possibly CV/CV. Venation characters of teeth not preserved.

Discussion—This specimen is very poorly preserved, but it is readily distinguished from other toothed morphotypes in the UF 19404 locality by its distinctive teeth.

Entire-margined Laminae

Morphotype—Entire 1: “Star” (Figs. 2-15A-F).

Specimens—UF 19404-61659 (nc), 61662 (nc), 61664 (nc, p), 61667 (nc), 61668 (nc), 61671

(nc), 61673 (nc), 61676 (nc), 61677 (nc), 61680 (nc), 61682 (nc), 61688 (104), 61692 (88, 89,

90, 91, 92), 61695 (nc), 61698 (200), 61705 (8), 61708 (31), 61712 (184), 61720 (77, 78), 61722

(4), 69290, 69291 (120).

Description—Laminae petiolate and marginally attached. Petiole over 2.5 cm long (19404-

61705) and >2 mm wide (specimens 19404-61664, 61712). Length to width ratio on seven specimens averaged to 3.1:1 with a range of 2.4:1 to 3.5:1. Laminae and fragments microphyllous to mesophyllous. Shape varies from ovate to elliptic to oblong. Medially

symmetric to slightly asymmetric in width. Base, when preserved, often asymmetric or more commonly with basal insertion asymmetry. Laminae unlobed and untoothed. Apex acute, straight to acuminate. Base acute to obtuse to ~90° and straight to convex to rarely concavo-convex.

Primary venation pinnate; possible naked basal veins present. Secondaries brochidodromous to occasionally almost eucamptodromous, regularly spaced and angled (~50-70°, usually ~60° in center of leaf, closer to 70° near base). Secondaries with excurrent to rarely decurrent attachment to midvein. Intersecondaries present; approximately perpendicular to midvein, more than 50% of subjacent secondary in length, distal course perpendicular to subjacent major secondary, less than one per intercostal area. Higher order venation irregular reticulate.

Discussion—These laminae appear to represent leaflets based on the strong asymmetry of the base (e.g., Figs. 2-15E, F). The petiole, a portion of which is visible in Fig. 2-15C, appears not to be pulvinate, so they likely do not represent legumes. The possibility of Sapindalean affinity can be considered, and there is some similarity with the pinnately compound leaves that have been called Cedrela shimperi (Lesquereux) MacGinitie.

Morphotype—Entire 2: “Triangle” (Figs. 2-16 A-F).

Specimens—UF 19404-61674 (nc), 61689 (12), 61690 (100? 108?), 61699 (42), 61700 (72),

61708 (29).

Description—Marginally attached leaves notophyllous to mesophyllous (a few fragmentary specimens microphyllous). Shape elliptic to oblong. Base likely asymmetrical; medial symmetry not preserved. Leaves unlobed and untoothed. Apex not preserved. Base acute and convex.

Primary venation pinnate. Secondaries brochidodromous. Secondaries regularly to irregularly spaced with a uniform angle (~55-65° mid-lamina; ~75° near base). Secondaries with excurrent to occasionally decurrent attachment to the midvein. Secondaries occasionally branch

in a “Y” shape (bifurcate once) as they approach the margin. Intersecondaries present; perpendicular to midvein. Intersecondary distal course perpendicular to subjacent major secondary; intersecondary frequency less than one per intercostal area. Tertiaries mixed percurrent, mostly opposite, some with an irregular course, with an obtuse angle to the midvein.

Epimedial tertiaries perpendicular to midvein. Higher order venation irregular reticulate (rarely preserved).

Discussion—These laminae have a stout primary and the secondaries are more irregularly spaced than morphotype Entire 1.

Morphotype—Entire 3: “Upside down triangle” (Figs. 2-17A-B).

Specimen—UF 19404-61687 (65).

Description—Marginally attached fragment, microphyllous. Apex missing; base acute, cuneate.

Primary venation pinnate, secondaries likely brochidodromous, but not clearly preserved.

Secondaries irregularly spaced. Higher order venation not well-preserved.

Discussion—This lamina has a much narrower base than the other entire-margined laminae from the UF 19404 quarry.

Morphotype—Entire 4: “Circle” (Figs. 2-18A-B).

Specimen—UF 19404-61713 (51).

Description—Leaf fragment notophyllous, lamina unlobed and untoothed. Apex acute and straight to acuminate; base not preserved. Primary venation pinnate; secondaries likely brochidodromous with excurrent attachment. Tertiaries not clearly preserved, some higher order venation reticulate.

Discussion—This lamina has a very long, narrow, acute apex (longer than morphotype Entire 8).

The secondaries are widely and irregularly spaced.

Morphotype—Entire 5: “Long rectangle = Cedrela Star” (Figs. 2-19A-C).

Specimens—UF 19404-61664 (nc, lighter leaf with no petiole), 61684 (82), 61707 (133).

Description—Marginally attached leaves (or fragments) microphyllous to mesophyllous.

Incomplete length 10.8 cm, width 4.9 cm on specimen 19404-61707. Shape elliptic to oblong.

Laminae appear symmetric, but no specimen complete. Laminae unlobed and untoothed. Apex missing on all specimens; base obtuse and convex possibly varying to rounded or cordate.

Primary venation pinnate; agrophics absent. Secondaries brochidodromous and regularly spaced with the angle to the midvein smoothly increasing proximally (~55° mid-lamina to ~90° near the base). Secondaries with excurrent attachment to the midvein. Intersecondaries present; perpendicular to midvein. Higher order venation not preserved.

Discussion—Informally, I call this “Cedrela star” because the laminae have some similarity to fossils that have been assigned to Cedrela (Meliaceae). The secondaries are closely spaced with excurrent attachment to the midvein and they diverge at close to 90° near the base of the lamina, all features that have been observed in other leaves with affinities to Cedrela.

Morphotype—Entire 6: “Angular squiggle” (Fig. 2-20A).

Specimen—UF 19404-61661 (nc).

Description—Lamina microphyllous, incomplete length 6.2 cm, width 2.2 cm. Lamina unlobed and untoothed. Apex and base acute. Primary venation pinnate. Secondaries brochidodromous with excurrent attachment. Higher order venation not preserved.

Discussion—This lamina has prominent brochidodromous secondary venation with relatively large loops after the main secondary vein contacts the subjacent secondary. The midvein is stout for the size of the leaf and the distance between secondaries increases toward the leaf apex.

Morphotype—Entire 7: “Angular parallelogram” (Figs. 2-21A-B).

Specimens—UF 19404-61665 (nc), 61721 (7).

Description—Marginally attached leaves microphyllous to notophyllous. Shape ovate to elliptic.

Medially symmetric. Laminae unlobed and untoothed. Apex acute, likely straight (not complete); base acute. Primary venation not clear (base not complete), possibly acrodromous. Midvein stout. Secondaries likely brochidodromous. Prominent pair of acute basal secondaries (~20° from midvein) ascend approximately half the length of the lamina, no other secondaries diverge in base of lamina. Tertiaries mixed percurrent, opposite more common. Fourth and fifth order venation irregular reticulate.

Discussion—This leaf type with a strongly ascending basal pair of secondaries and an entire margin, is typical for many Lauraceae, (e.g., Cinnamomum).

Morphotype—Entire 8: “Y” (Figs. 2-22A-E).

Specimens—UF 19404-61701 (185), 61704 (84), 61712 (183).

Description—Marginally attached microphyllous to notophyllous laminae. Shape elliptic; medially and basally symmetric. Laminae unlobed and untoothed. Apex acute (narrow) and straight; base acute and slightly convex.

Primary venation pinnate; secondaries brochidodromous. Some secondaries branch dichotomously (“Y” shape) about halfway to 2/3 of the way to the margin. Secondaries uniformly spaced and angled (~50-60°) with excurrent attachment. Intersecondaries present; perpendicular to midvein. Distal course of intersecondary perpendicular to basiflexed. Some spaces between secondaries with more than one intersecondary, but intersecondaries not well- preserved through entire lamina. Tertiaries percurrent. Higher order venation irregular reticulate.

Areolation well-developed; freely ending veinlets visible.

Discussion—A distinguishing feature of this morphotype is that the secondaries branch dichotomously in a “Y” shape as they travel toward the margin. This occasionally occurs in morphotype Entire 2, but the branches in those specimens occur closer to the margin. Entire 2 tends to have larger laminae and fewer intersecondaries than Entire 8. Entire 8 also has more regularly spaced secondaries with a slightly smaller angle to the midvein as compared to Entire

Morphotype—Entire 9: “Teardrop” (Figs. 2-23A-C).

Specimen—UF 19404-61670 (nc).

Description—Lamina notophyllous, incomplete length 9 cm, width 4 cm. Shape ovate.

Asymmetric in width, base not preserved. Lamina unlobed and untoothed. Apex acute and straight to acuminate. Primary venation pinnate; simple agrophics present. Major secondaries brochidodromous. Secondaries irregularly spaced with secondary spacing abruptly increasing proximally, one pair of acute basal secondaries. Intersecondaries present, proximal course variable ranging from parallel to perpendicular. Intersecondary length variable; distal course most frequently perpendicular to subjacent major secondary. Tertiaries percurrent where visible.

Higher order venation percurrent to reticulate.

Discussion—Although this morphotype has one pair of acute basal secondaries, they does not extend as far up the leaf blade as observed in morphotype Entire 7.

Morphotype—Entire 10: “Teardrop Y” (Fig. 2-24A).

Specimen—UF 19404-61719 (2).

Description—Likely marginally attached microphyllous lamina. Shape ovate, unlobed.

Symmetry could not be determined. Margin untoothed. Apex acute; base likely obtuse. Primary venation pinnate. Agrophics present, compound. Secondaries likely brochidodromous.

Secondary spacing irregular or gradually increasing proximally. Secondaries with excurrent attachment to midvein. Intersecondaries not observed. Tertiaries mixed percurrent. Higher order venation not preserved.

Discussion—Although this leaf has broad similarities to morphotypes Entire 7 and Entire 9, the major and minor secondaries in this specimen branch in a “Y” as they travel toward the margin which was not observed in the other morphotypes.

Morphotype—Entire 11: “Sguiggly box” (Figs. 2-25A-B).

Specimens—UF 19404-61708 (30), 61710 (202).

Description—Laminae microphyllous; shape likely elliptic (base and apex missing). Laminae untoothed. Primary venation likely pinnate. Secondaries brochidodromous. Secondaries widely spaced with somewhat uniform spacing and angle (narrower divergence angle toward the base

~40-45°, wider divergence angle toward the apex ~70°) where visible. Secondaries with excurrent to decurrent attachment. Intersecondaries not observed. Tertiaries mixed percurrent where visible. Higher order venation not preserved.

Discussion—The secondaries in this morphotype are more widely and irregularly spaced than the most abundant entire morphotype at the UF 19404 site, Entire 1: “Star.”

Morphotype—Entire 12: “IS” (Figs. 2-26A-B).

Specimen—UF 19404-61683 (165).

Description—Notophyllous fragment, full lamina at least mesophyllous. Margin untoothed. Base and apex missing. Primary venation pinnate. Secondaries regularly spaced and angled where visible with decurrent attachment. Intersecondaries present, variable from parallel to major secondaries to perpendicular to midvein (some secondaries diverge at close to 90°).

Intersecondary distal course basiflexed to perpendicular where preserved. More than one

intersecondary per intercostal area. Tertiaries alternate percurrent to slightly irregular reticulate.

It almost appears that both major and minor intersecondaries present. Quaternary and quinternary venation irregular reticulate. Areolation present.

Discussion—The secondaries in this morphotype diverge at a broader angle (closer to 90°) than other entire margined specimens from the UF 19404 quarry. Morphotype Entire 12 can also be distinguished by its numerous, prominent intersecondaries and the secondaries often have decurrent attachment to the midvein.

Morphotype—Entire 13: “Loopy Squiggle” (Figs. 2-27A-D).

Specimens—UF 19404-61672 (nc), 61703 (161, leaf on top with margin).

Description—Marginally attached laminae, microphyllous to notophyllous. Incomplete length

8.5 cm, width ~5 cm for a length to width ratio of 1.7:1 (19404-61672). Shape ovate. Laminae appear symmetric but neither specimen completely preserved. Laminae unlobed and untoothed.

Apex acute and straight; base obtuse and straight where visible.

Primary venation pinnate; simple agrophics present. Major and minor secondaries brochidodromous. Marginal secondary present. Major secondaries regularly spaced and angled

(~40 to 60°) with excurrent attachment. Intersecondaries not observed. Tertiaries mixed percurrent where visible with an obtuse angle to the midvein. Exterior tertiaries looped. Higher order venation irregular reticulate, where visible.

Discussion—This morphotype has more regular and evenly spaced secondaries than other specimens from the UF 19404 locality. The marginal secondary is also a good character to use to help recognize this morphotype.

Morphotype—Entire 14: “Populus no teeth” (Fig. 2-28A).

Specimen—UF 19404-68888 (186).

Description—Marginally attached, mesophyllous lamina. Full lamina not preserved, but intact portion suggests an ovate laminar shape. Base slightly asymmetrical. Lamina unlobed and untoothed. Apex not preserved; base obtuse and convex in shape. Primary venation pinnate.

Strong basal secondaries with secondary spacing appearing to gradually increase proximally.

Secondary angle appears to smoothly decrease proximally; secondaries with excurrent attachment to the midvein. Tertiaries mixed percurrent with more opposite than alternate. Basal tertiaries form a gentle chevron that points toward the apex of the lamina. Tertiaries perpendicular to the midvein. Higher order venation reticulate, very faintly preserved.

Discussion—This specimen superficially looks like Populus, but lacks teeth and has more regular venation. This morphotype can be distinguished from Populus, Grewiopsis, and other morphotypes from the UF 19404 locality with its thick gauge pinnate primary venation, subopposite basal secondaries, marginal or close intramarginal thin secondaries, epimedial tertiaries that are perpendicular to the midvein, looped marginal tertiaries, and percurrent tertiaries that are mostly opposite, with some alternate. The basal secondaries in Populus travel further up the lamina at a steeper angle than those observed in morphotype Entire 14.

Furthermore, if this was specimen of Populus, teeth would be preserved. Specimens assigned to

Grewiopsis generally have 5 prominent basal veins with a broader base that is not as elongated as morphotype Entire 14. This morphotype was also compared to similar specimens within the UF

19404 (including Teardrop, Teardrop Y, and Angular Parallelogram) quarry, but the venation differs enough to warrant placement of this specimen in its own morphotype. However, this specimen was matched to morphotype “WSB” from the upper horizon at Blue Rim.

Summary of Isolated Channel Fill Leaves, Locality UF 19404

The isolated channel fill, UF 19404, preserves 28 generally poorly preserved dicotyledonous leaf morphotypes. Fourteen are toothed, however, 10 are based on single, partial

specimens. Two based on single specimens (Toothed 9 and 11) have features in common with

Macginitiea and may not be representative of distinct species. There are also 14 untoothed morphotypes with 7 based on single specimens. This relatively high diversity deposit (for the number of specimens) and lack of small, reproductive structures (as found in the lower horizon) suggests an allochthonous deposit. Poor preservation did not allow for many hypotheses of taxonomic affinities, but the presence of Platanaceae (Macginitiea), Sapindaceae (Serjania), and specimens with affinities to Ulmaceae (cf. Cedrelospermum), Anacardiaceae (cf. Rhus), possibly other Sapindales, and Lauraceae is indicated. Monocots are rare, but present. Specimen UF

19404-61666 is a fragment of a monocot leaf with thicker guage parallel veins ~1-2 mm apart with thinner parallel veins in between, no midvein is visible. Occassional ferns including

Asplenium sp. and Lygodium kaulfussi (UF 19404-61669) are also present.

Part II: Dicotyledonous Leaf Morphotypes from the Lower Horizon

Toothed Laminae

Morphotype—HT: “Horizontal Tertiaries” (Figs. 2-29A-G).

Species—new (in the tribe Homalieae, Salicaceae).

Localities—UF 15761, 15761N, 19225.

Specimens—UF 15761-22733, 22739, 22746, 43043; UF 15761N (2012)- 57186, 57188, 57190,

57193, 57194, 57195, 57196, 57197, 57200, 57201, 57202, 57204, 57205, 57206, 57207; UF

15761N (2014)-43923, 43938, 43980, 43950, 43974, 43990, 43997 (f), 61379, 61381, 61414,

61452, 61455, 61466, 69729 (?, f); UF 19225-51968 (?), 51969 (f), 51970 (HOV pp), 51971

(HOV pp), 51975 (?), 51979, 56938, 56968 (pp), 56972 (nm), 57023 (pp), 57024 (pp), 57062,

57063.

Description—Leaves petiolate with marginal attachment. Blade notophyllous and elliptic.

Length to width on two mostly complete specimens 8.6:4.6 cm and 8.1:4.1cm for ratios of 1.9:1

and 2.0:1, respectively. Symmetrical both medially and basally. Leaves unlobed with a serrate margin. Apex acute and straight to acuminate. Base angle variable, usually ~90° with a cuneate to convex shape.

Venation pinnate; secondaries semicraspedodromous. Agrophic veins and interior secondaries absent. Major secondary spacing regular. Variation of major secondary angle to midvein smoothly decreasing toward base. Excurrent attachment of secondaries to midvein.

Intersecondaries absent. Tertiaries opposite percurrent with a straight course. Intercostal tertiaries consistent in vein angle. Epimedial tertiaries opposite percurrent. Exterior tertiaries variable.

Quaternaries mixed percurrent. Quinternary vein fabric reticulate. Areolation present, but poorly preserved. Marginal ultimate venation looped.

One order of teeth with 4-5 per centimeter. Sinuses angular. Tooth shape convex/convex.

Principal vein present with marginal termination, entering the tooth supramedially, sometimes along the apical flank; principal vein terminates at the nadir of the superjacent sinus. Major accessory vein follows a convex course; tooth apex cassidate.

Discussion—The thin petiole, glandular teeth, the regular, opposite percurrent tertiaries, and the lack of teeth in a short section in the base of the lamina are informative characters in this morphotype. Similar specimens have also been recovered from Eocene sites (e.g., PA 108, PA

114) in northwestern Wyoming. These specimens have morphological similarities to Rhamnus L.

(Rhamnaceae) and Luehea Willd. (Malvaceae). In many Rhamnaceae, the principal vein enters the tooth in the lower portion, rather than the upper portion as observed in this species.

MacGinitie (1974) documented a species of Luehea in the Kisinger Lakes flora, Luehea newberryana. Extant Luehea leaves often have a pair of basal secondaries that travel more than

2/3 the length of the leaf with a large gap before the next secondaries diverge from the midvein;

this feature is not present in the fossil leaves. Furthermore, the teeth on many living species of

Luehea are smaller, more angular, and more numerous (and occasionally in two orders) than those observed on the fossil leaves described here. Fossil leaves assigned to Styrax L.

(Styracaceae), from the Green River Formation (MacGinitie, 1969), also share some features with these Blue Rim specimens. However, none of these extant or fossil taxa are identical to the leaves considered here.

Ultimately, this leaf type was identified after being matched with co-occurring flowers preserved in the same sediments at Blue Rim. The flowers, with in situ pollen, have been assigned to the tribe Homalieae within Salicaceae s.l. (see Chapter 3). An examination of herbarium specimens of extant taxa in Homalieae, revealed the similarities between the leaves of that tribe and this morphotype. Many salicaceous leaves have three strong basal veins, however none of the genera in Homalieae or these Blue Rim specimens do.

Morphotype—VCT: “Variable Cedrela Toothed” (Figs. 2-30A-F).

Localities—UF 15761, 15761N, 15761S, 19225, 19337.

Specimens—UF 15761-55195, 55232, 55233, 55238; UF 15761N (2012)-57251, 57421 (f),

57629 (p, pp), 57630, 57631, 57632, 57633, 57634, 57635, 57636, 57639 (p), 57641, 57642,

57643, 57651, 57668 (f), 57671 (?, f, p), 57674 (f); UF 15761S (2012)-57906 (f, p); UF 15761N

(2014)-43924 (15, ?, f, nm), 43928, 43932, 43936 (?, f, p), 43937, 43940, 43941, 43951, 43952,

43961, 43963, 43986, 43987, 43988, 43995 (f), 43996 (25), 43997, 43999, 61375, 61382, 61402,

61410, 61414, 61415, 61422 (c), 61437 (pp), 61444, 61453 (151), 61458, 61459, 61479, 61467

(?, p); UF 19225-57102; UF 19337-58043, 58096, 61519, 61555.

Description—Marginally attached petiolate leaves (leaflets?) ranging from microphyllous to notophyllous. Length to width ratio averages to 3.7:1 based on eight mostly complete laminae.

Laminae elliptic, medially symmetrical; base ranges from ~symmetrical to slight basal width asymmetry; many with clear basal insertion asymmetry. Laminae unlobed and vary from untoothed to serrate. Apex acute and ~straight (leaves often preserved in a curved position). Base angle variable from acute, to ~90 degrees to obtuse. Base shape variable depending on asymmetry and angle, but varying from convex to straight to concavo-convex.

Primary venation pinnate; ~one basal vein (but possible naked basal veins, secondaries).

Agrophics absent. Secondaries arch toward margin; eucamptodromous to brochidodromous.

Major secondaries regularly to irregularly spaced with an ~uniform angle to midvein.

Secondaries with excurrent attachment to midvein; secondaries occasionally fork (Y) as they travel toward margin. Intersecondaries present; parallel to major secondaries; less than one per intercostal area; intersecondary distal course perpendicular to subjacent major secondary to basiflexed. Tertiaries mixed percurrent with an irregular course. Angle of tertiaries projected to midvein obtuse. Epimedial tertiaries ~perpendicular to midvein. Exterior tertiaries looped.

Higher order venation poorly preserved; appears irregular reticulate.

One order of teeth present, varying from regularly to irregularly spaced, with large expanses of margin lacking teeth frequent. Where present, 1-3 teeth preserved per centimeter.

Sinuses angular; tooth shape CV/CV to ST/CV to ST/ST. Principle vein present (only visible on a few specimens) with marginal termination between the tooth apex and the nadir of the superjacent sinus.

Discussion—This morphotype is similar to TCE (True Cedrela Entire, described below), but differs in that it often has teeth and the base is frequently asymmetrical (sharp basal insertion asymmetry). In addition, the major secondaries in VCT are more irregularly spaced and arching

in comparison to the TCE. Finally the base of the VCT specimens is generally more acute than in specimens of TCE.

Morphotype—SR: “Serjania rara” (Figs. 2-31A-J).

Species—Serjania rara MacGinitie.

Localities—UF 00340, 15761, 15761N, 15761S, 18288, 19225, 19225N, 19032, 19031, 19337.

Specimens—UF 00340-58300; UF 15761-22621, 48496 (?, pp), 53538, 55211 (?, pp), 55212,

55213, 55214, 55223 (?), 55224, 55227, 55228, 56338; UF 15761N (2012)-57219, 57266,

57311, 57387, 57388, 57389, 57390, 57391, 57392, 57393, 57394, 57395, 57396, 57397, 57398,

57399, 57400, 57401, 57402, 57403, 57404, 57405, 57406, 57407, 57408, 57411, 57412, 57413,

57414, 57415, 57416, 57417, 57418, 57419, 57420, 57421, 57422, 57423, 57425, 57447, 57628,

57698; UF 15761N (2014)-43934, 43955, 43976, 43977, 43981, 43992 (157, 158, ?, f), 43995

(f), 61377, 61412, 61424, 61430, 61434, 61438, 61454 (cp is 61496’’), 61458, 61464, 61466; UF

15761S (2012)-57786, 57787, 57788, 57789, 57790, 57791, 57792, 57793, 57794, 57795,

57796, 57823, 57844 (?, pp), 57846, 57874 (f), 57894 (?, ls, f), 57901 (?, ls, pp), 57917, 57933

(ls, pp); UF 15761S (2014)-61503 (31; ?, pp), 61504 (4, 5), 61505 (3), 61506 (2; ?, pp), 61507

(9), 61512 (32); UF 18288-58204 (pp); UF 19031-39021, 56311; UF 19032-38999, 39004,

39009, 39011; UF 19225-51981, 52027, 52028, 52030, 52032 (?, pp), 52040, 52041, 52053 (pp),

52050, 52047, 52045 (ls, f), 54598, 54600 (?, pp), 54604, 54605, 54606, 54607 (c), 54608 (?, ls, pp), 54609 (ss, c), 54610, 56942, 57014, 57015, 57016 (c), 57017, 57018, 57019, 57020 (pp),

57040, 57093; UF 19225N-57956, 57960, 61817; UF 19337-57984, 61533.

Description—Petiolate leaflets marginally attached. Leaves compound (but leaves with multiple leaflets rare at Blue Rim). The terminal leaflet tends to be more symmetrical than the lateral leaflets (e.g., 15761N-61424). Leaflets microphyllous. Length to width ratio of leaflets averages

to: 2.0:1 (measurements from 9 mostly complete leaflets). Shape usually elliptic. Many specimens (likely lateral leaflets) asymmetrical. Some of the teeth are large enough to be recognized as pinnate lobes. Apex acute and straight to slightly convex. Base acute, rarely obtuse; straight to convex in shape.

Venation pinnate. Secondaries craspedodromous. Interior secondaries absent. No obvious marginal venation. Specific characters of secondary venation not well-preserved.

Intersecondaries present. Higher order venation not preserved.

Margin serrate. Large teeth treated here as lobes. Basal portion of leaflets entire. One order of teeth; one to two teeth per centimeter. Sinuses angular; tooth shape convex/convex.

Principal vein present; terminates at the apex of the tooth. Apex of tooth frequently pointed, occasionally spinose (e.g., 15761N-61464), possible continuation of principal vein.

Discussion—This morphotype encompasses a lot of variation, but is likely representative of a single taxon with both terminal and lateral leaflets preserved. These leaflets are similar to

Lomatia colorandensis (Knowlton) Brown (Brown, 1929, 1934) which was later synonomized with Cardiospermum coloradensis (Knowlton) MacGinitie (MacGinitie, 1969) from the Green

River Formation. However, many of the Cardiospermum coloradensis specimens in the Green

River Formation are much more deeply lobed than the Blue Rim specimens. The Blue Rim material has more morphological similarities with specimens assigned to Serjania rara

MacGinitie (but unfortunately not with the holotype of that species) from the Kisinger Lakes site in northwestern Wyoming (MacGinitie, 1974). Occasionally, Blue Rim specimens look more similar to Cardiospermum L.. For example, specimen UF 19032-39004 matches the morphology of a terminal leaflet of Cardiospermum. Extant Cardiospermum and Serjania Mill. are closely related (Sapindaceae, subfamily Sapindoideae; tribe Paullinieae).

Species of extant Serjania are lianas with compound leaves. Most of the leaflets at Blue

Rim are detached, but they are occasionally found in attachment, indicating a compound leaf.

Modern Serjania species have variable ecological preferences with 50% of species found in thickets of open and dry vegetation. Another 35% of species are found in the margins of gallery forests, while 8% of species prefer disturbed areas or gaps in dense tall humid forests (Acevedo-

Rodríguez, 1993). Today, Serjania is only found below 3000 m elevation. A related species,

Paullinia L., prefers humid dense forests, which contrasts with the drier and more open preference of extant Serjania (Acevedo-Rodríguez, 1993).

Morphotype—AF: “Aleurites fremontensis” (Figs. 2-32A-H).

Species—“Aleurites” fremontensis (Berry) MacGinitie.

Localities—UF 15761, 15761N, 15761S, 18288?, 18289, 19225?, 19337.

Specimens—UF 15761-55203, 55204, 55205, 55206; UF 15761N (2012)-57174 (?, f), 57268 (f, ss), 57269 (?, f), 57277 (?, f), 57409 (ss), 57420 (f), 57450, 57451, 57452, 57453, 57454, 57455,

57456, 57457, 57458, 57459, 57460, 57461, 57462, 57463, 57464, 57465, 57466, 57467, 57468,

57469, 57470, 57471, 57472, 57473, 57474, 57475, 57476, 57477, 57478, 57658 (?, f), 69723,

69724, 69725, 69726, 69727, 69728; UF 15761N (2014)-43929, 43939, 43949, 43950, 43985,

43996 (38, 39), 61380, 61410 (?, f), 61411, 61413, 61416, 61418?, 61424 (?, f); UF 15761S

(2012)-57863, 57870 (?, f), 57871, 57905; UF 18288-58197 (?, pp, f), 58198 (?, pp, f), 58203

(?); UF 18289-56286, 56299, 56300, 56301, 56302, 56303, 56350; UF 19225-52034 (f), 57002

(?, pp); UF 19337-61526 (f).

Description—Leaves petiolate with marginal attachment. Petiole long (e.g., >4.5 cm). Leaves mesophyllous, occasionally notophyllous, rarely microphyllous. Length to width ratio averaged to ~1.1:1 from 5 mostly complete specimens (Range: 0.9:1 to 1.4:1). Laminae elliptic,

symmetrical, palmately lobed and toothed (serrate). Apex acute, straight. Base obtuse; base shape variable from cuneate to convex. Laminar surficial glands present.

Primary venation palinactinodromous. Naked basal veins present; 7 basal veins.

Agrophics present. Secondaries semicraspedodromous. Interior secondaries occasionally present.

Minor secondaries semicraspedodromous. Marginal secondary or closely spaced laminar glands all along leaf margin. Secondaries regularly spaced (or gradually increasing proximally).

Variation of major secondary angle to midvein ~uniform. Major secondaries with excurrent attachment to the midvein. Intersecondaries absent. Tertiary veins mixed percurrent.

Perpendicular angle of tertiaries to primary; angle increases exmedially. Epimedial tertiaries mixed percurrent and perpendicular to the midvein. Exterior tertiaries looped. Quaternaries irregular reticulate. Quinternaries irregular reticulate. Areolation present, good development.

Freely ending veinlets absent (may not be preserved).

Margin serrate. One order of irregularly spaced teeth. Two to three teeth per centimeter, occasional small areas where teeth more numerous (up to 6 per cm). Sinuses rounded to angular.

Tooth shape varies from ST/ST to ST/CV to CC/CV to CC/ST. Principle vein present, entering submedially; termination unclear. Tooth apex not spinose.

Discussion—This morphotype, even when fragmentary, is easily recognized by the numerous dark pigmented dots (glands) scattered across the laminar surface and its long petiole (when preserved). These fossil specimens are most similar to those MacGinitie (1974) called Aleurites fremontensis from the Kisinger Lakes flora. There is also a species attributed to Aleurites from the Green River Formation (A. glandulosa), but it does not have the regular small teeth that are present in the Kisinger Lakes and Blue Rim specimens (MacGinitie, 1969).

The fossil specimens share features with modern Aleurites including a long, stout petiole, fine dots scattered across the leaf surface (likely trichome bases as the modern leaves are quite pubescent), venation pattern, and leaf shape. Modern species of Aleurites can have variable leaves on the same individual with a range from unlobed to >5 lobed leaves (Dickey et al., 1952).

The fossils have no lobes or more frequently three lobes. However, the fossils lack (or don’t preserve) the two prominent circular glands on the petiole near the junction with the lamina found in modern species of Aleurites. These two circular glands are much larger than the small, scattered dots present across the laminar surface of the fossils.

Morphotype—PC: “Populus cinnamomoides” (Figs. 2-33A-I).

Species—Populus cinnamomoides (Lesquereux) MacGinitie.

Localities—UF 15761, 15761N, 15761S, 18288, 19031, 19032, 19225, 19337, 19338.

Specimens—UF 15761-22711, 22768, 22795, 43014 (ls, pp), 43015, 43016, 43017, 43018 (ls, pp), 43019, 43021, 43022, 43023, 43025, 43026, 43027, 43028, 43029, 43030, 43031, 43032,

43033, 43034, 43035, 43036, 43037, 43038, 43039, 43040, 43042, 43044, 43045, 48462 (?, pp),

48463, 48496, 48500, 48502, 48597, 49830, 54573, 55202, 55207, 55209, 55218 (?), 55220,

55226, 55254, 69731; UF 15761N (2012)-57199, 57479 (really long teeth), 57482 (also slightly fatter), 57484, 57578 (super skinny), 57582, 57583, 57584, 57585, 57586, 57587, 57588 (fatter),

57590, 57591, 57592, 57594, 57674; UF 15761N (2014)-43935, 43958, 43965 (?), 43982,

43983, 43993 (50, ?), 43997, 61490, 61494, 61497; UF 15761S (2012)-57800, 57803, 57808,

57842, 57862, 57868, 57869, 57885; UF 18288-58190, 58191, 58192; UF 19031-39015, 39020,

39023, 56310; UF 19032-38988 (ls), 38998, 39005; UF 19225-51959, 51960, 51961, 51962,

51963, 51964, 51965, 51966, 51967, 51980, 52026, 52036 (slightly broader base), 52051, 54559,

54578 (?, ls, f), 54580, 54581, 54582, 54583, 54584 (1 lobed, damaged?), 54585, 54589, 54590,

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54591, 54592, 54593, 54594, 54595, 54596 (f), 54587, 54611 (?, f), 54613, 54615, 54617 (1 lobed, damaged?), 57052 (?, ls, f), 57053, 57054, 57055, 57056, 57058, 57059, 57060 (broader specimen), 57061 (?, ls, pp), 57064, 57065, 57066, 57067, 57068, 57069, 57070, 57071, 57124;

UF 19337-57986, 57988, 57994 (f), 58056, 58069, 61521 (?), 61522, 61529 (weak tooth development), 61539, 61540, 61542, 61554 (medium sized, dark), 61555 (?, pp), 61556, 61557,

61558, 61571, 61572, 61583, 61592 (f), 61597 (f); UF 19338-58281, 61878, 61879, 61880,

61882.

Description—Marginally attached petiolate leaves. Petiole long (e.g., >3 to >4.5 cm). Laminae microphyllous to notophyllous to occasionally mesophyllous. The length to width ratio of 14 mostly complete specimens averaged to ~3.2:1 (Range: 1.9:1 to 5.5:1). Shape elliptic to ovate.

Medially symmetric to slightly asymmetric. Base symmetrical. Leaves unlobed and toothed.

Apex acute and straight. Base acute to ~90° to occasionally obtuse. Base shape cuneate to slightly convex.

Primary venation pinnate, almost actinodromous. Naked or nearly so basal veins present;

3 basal veins. Agrophics present. Major secondaries semicraspedodromous. Fimbrial vein present. Secondary spacing abruptly increasing proximally. One pair of acute basal secondaries present. Secondaries with excurrent attachment to the midvein. Intersecondaries present, parallel to major secondaries, more than 50% of subjacent secondary, distal course reticulating/ramifying, less than one per intercostal area. Tertiaries mixed percurrent—more regular on larger leaves and more irregular on smaller/narrower leaves. Tertiaries with a slightly acute angle to the midvein. Quaternaries and quinternaries irregular reticulate. Areolation present, moderate to good development. Freely ending veinlets present, branched.

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One order of regularly to slightly irregularly spaced teeth, two to three per centimeter.

Sinuses angular to slightly rounded. Teeth CV/CV in shape varying to CV/ST, sometimes more appressed and other times more prominent. Principle vein present, terminating on the distal flank. Accessory veins present. Tooth apex nonspecific glandular, likely tylate.

Discussion—This morphotype encompasses a wide range of variation, especially in shape.

Specimens range from long and skinny to much wider. Extant Populus species can also include a wide range of morphological variation (Eckenwalder, 1980).

Populus, predominately represented by leaf fossils, has one of the better fossil records in

Salicaceae. Populus is composed of ~35 extant species in six sections (Abaso, Aigeiros,

Turanga, Leucoides, Tacamahaca, and Populus) and has a mostly north temperate distribution

(Eckenwalder, 1996; Hamzeh et al., 2006). Poplars are fast growing, deciduous, dioecious trees with serrate leaf margins and wind pollinated catkin inflorescences. Extant poplars are often pioneer species in boreal forests and riparian areas; they require high soil moisture contributing to their presence near water bodies (Hamzeh and Dayanandan, 2004; Hamzeh et al., 2006). This preference has likely contributed to the prominence of leaves of Populus in the fossil record.

Seasonal heterophylly (early leaves that overwintered in the buds have a different shape and serration than late leaves) is common in Populus and this has likely contributed to taxonomic confusion and over-splitting by paleobotanists (Eckenwalder, 1977, 1980; Collinson, 1992).

Other poplar species have distinct differences between the leaves of juvenile and adult plants.

Fossil poplars such as P. cinnamomoides, P. adamantea, and P. cedrusensis have all been thought to be related to extant species that display heterophylly including P. mexicana

(Eckenwalder, 1980). Foliar heteromorphism may contribute to the wide morphological variation

(long and narrow to much wider in shape) in the leaves of P. cinnamomoides from Blue Rim. In

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addition, leaves growing on stump sprouts off a mature tree often have different morphological characters than the leaves from the crown of the tree.

The oldest likely record of Populus (sect. Abaso) is from the latest Paleocene (~58 Ma) of

North Dakota (Bear Den Member of the Golden Valley Formation, Hickey, 1977; Manchester et al., 1986; Collinson, 1992). Two specimens called Cercidiphyllum genetrix (Newberry) Hickey in Hickey’s (1977) work were later recognized to be representative of Populus (Manchester et al., 1986; Collinson, 1992). Populus (sect. Abaso) is also well represented in the Eocene with specimens from the Green River Formation of CO, UT and WY (MacGinitie, 1969; Manchester et al., 2006). It has been hypothesized that Populus cinnamomoides and Populus wilmattae are the same taxon with P. cinnamomoides representing the juvenile leaves and the broader P. wilmattae representative of the adult leaves (Eckenwalder, 1977, 1980; Manchester et al., 1986).

However, more recent work has noted that these two taxa are geographically isolated

(Manchester et al., 2006) with P. cinnamomoides found in the former Lake Gosiute of Wyoming and P. wilmattae found in the Parachute Creek Member of the Green River Formation (Lake

Uinta) in Utah and Colorado (Manchester et al., 2006). Other Eocene localities with records of

Populus include the McAbee flora of British Columbia, the Puget Group of Washington, and the

Claiborne Formation of TX and TN (Eckenwalder, 1980; Dillhoff et al., 2005).

Morphotype—GBT: “Grewiopsis Bulbous Teeth” (Figs. 2-34A-E).

Localities—UF 15761, 15761N, 15761S, 19337.

Specimens—UF 15761-43020, 48461; UF 15761N (2012)-57329 (?, f, pp, p), 57483 (?, f, p),

57490, 57593 (pp, f), 57607 (?, f, pp), 57608 (?); UF 15761N (2014)-61465, 61468, 61470 (130,

?, p, pp): 61471, 61499; UF 15761S-57846 (?), 57873(?); UF 19337-57985, 58064 (f), 61518,

61570, 61592.

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Description—Leaves marginally attached, petiolate, and microphyllous to notophyllous, rarely mesophyllous. The length to width ratio on 4 mostly complete specimens averaged to ~1.7:1

(Range: 1.3:1 to 2.4:1). Leaves symmetric, unlobed and toothed. Apex acute, straight; base obtuse and rarely cuneate, more frequently convex.

Primary venation pinnate with two prominent actinodromous-like secondaries. Naked basal veins absent?, with 5 basal veins. Agrophics present. Secondaries unclear. Tertiaries mixed percurrent. Higher order venation not preserved.

One order of regularly to irregularly spaced teeth. Two to five teeth per centimeter.

Occasionally teeth more closely spaced, regular and very globose, ranging to 8/cm (19337-

57985). Sinuses angular to rounded. Teeth often globose, CV/CV in shape, occasionally with a rounded tip and straight flanks. Details about tooth venation not preserved. Tooth apex occasionally (where visible) nonspecific.

Discussion—These specimens superficially resemble Grewiopsis wyomingensis Berry from the

Wind River basin in northwestern Wyoming (Berry, 1930), but are more likely related to

Cercidiphyllaceae (e.g., Trochodendroides). Crane (1984) noted that in the original diagnosis of

Grewiopsis (by Saporta) the leaves were untoothed. Similar morphotypes have been recovered at

PETM sites in the Bighorn Basin (northcentral Wyoming), the Green River Formation, and the middle Eocene Clarno Nut Beds (Oregon). Specimens of Cercidiphyllaceae have also been documented in the McAbee flora in British Columbia and the early Paleogene from Britian

(Crane, 1984; Dillhoff et al., 2005; Pigg et al., 2007).

It was challenging to separate these fossils from those of Populus cinnamomoides as many of the broad morphological features overlap. Grewiopsis has a more regular, orthogonal mesh pattern of higher order venation, whereas it is more irregular in Populus. However, most of

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the Blue Rim specimens are poorly preserved and higher order venation is not present. In contrast, specimens of P. cinnamomoides tend to have well-preserved higher order venation. In some cases, preservational quality can be taxonomically informative. The specimens from Blue

Rim assigned to GBT also have 5 major veins originating near the base of the lamina as compared to 3 in the PC specimens. In most P. cinnamomoides specimens and P. wilmattae, the teeth are continuous (although smaller) in the attenuate apex (MacGinitie, 1969); whereas in the

GBT specimens, teeth are absent in the apical portion of the leaf. In addition, teeth in specimens of GBT tend to point outward rather than upward as observed in specimens of PC.

This morphotype also shares features with some other fossil species of Populus. For example, the fragmentary specimen UF 15761N-57483 shares features with both the broad definition of PC and GBT. This specimen also has similarities to Populus quintavena

(MacGinitie, 1974). However, MacGinitie notes that P. quintavena has a slender petiole, whereas it is broad in the Blue Rim specimen (>3 mm where it attaches to the lamina). The number of teeth per cm (4) is similar between P. quintavena and specimen UF 15761N-57483.

However, the higher order venation on the Blue Rim specimen seems more organized than on other specimens assigned to Populus. The Blue Rim GBT specimens also have similarities to some specimens of P. wyomingiana from northwestern Wyoming (MacGinitie, 1974), but the poor preservation of the Blue Rim material precludes a full comparison.

Alternatively, these specimens could be the same species as P. cinnamomoides if it has foliar heteromorphism (due to seasonal variations or age; see previous discussion under PC).

Morphotype—TDA/PS: “Toothy Double Acute/Pseudosalix” (Figs. 2-35A-D).

Localities—UF 15761N, 15761S.

Specimens—UF 15761N-57410, 57652; UF 15761S-57877, 57883.

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Description—Leaves petiolate with marginal attachment, ranging from microphyllous to notophyllous. Partially preserved petiole 0.5 cm long by 1 mm wide (15761S-57883). Laminar length ~3.4 cm by 1.0 cm wide (15761S-57883); length 8.8 cm by ~3 cm wide for a L:W ratio of

2.9:1 (15761N-57652). Laminar shape elliptic with medial symmetry varying from symmetrical to slightly asymmetrical. Base, when preserved, asymmetrical in width (15761S-57883).

Specimens are unlobed and toothed (with crenate and serrate protrusions). Apex acute and straight, base acute and cuneate to convex.

Primary venation pinnate; laminae with one to three basal veins. Secondaries semicraspedodromous. Perimarginal veins sometimes present with possible intramarginal secondary (15761S-57883) and marginal secondary (15761N-57652). This difference could be representative of variations in preservation. Secondaries diverging at nearly 90° from the primary, with more acute angles in the basal part of the leaf. Secondaries irregularly spaced with one pair of acute basal secondaries. Secondaries with excurrent attachment to the midvein.

Intersecondaries present; perpendicular to the midvein. Intersecondaries fork and branch toward the base and apex and connect with the secondaries. Intersecondaries are slightly >50% of the length of the subjacent secondary. Tertiaries are poorly preserved but are likely irregular reticulate (varying to alternate percurrent). Higher order venation is reticulate.

One order of teeth range from regular to semi-regularly spaced on individual specimens.

However, number of teeth varies from ~2-8 per centimeter. Sinuses variable from angular to rounded. Tooth shape CV/CV. Principle vein present with marginal termination at the nadir of the superjacent sinus, occasionally varying closer to the distal flank. The major accessory vein in each tooth convex in relation to the principal vein.

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Discussion—The large range in the number of teeth per centimeter could be due to some of these leaves being immature or still in development. The presence of three strong basal veins is a taxonomically useful character (seen in Populus cinnamomoides). Other taxa from Salicaceae s.l. are also possible including Banara Aubl., Salix L., and Pseudosalix Boucher, Manchester, &

Judd. Pseudosalix handleyi Boucher, Manchester, & Judd was documented from the Eocene

Green River Formation in Utah (Boucher et al., 2003). This extinct taxon is sister to the clade containing extant Populus and Salix. Pseudosalix handleyi has a similar shape to this morphotype (especially Fig. 2-35D) and shares the character of irregularly spaced semicraspedodromous secondaries. The tertiaries are also similar. Differences between the Blue

Rim material and P. handleyi include the angle at which the secondaries branch from the midvein; it is ~90° in the Blue Rim specimens and 50-60° in Pseudosalix handleyi (Boucher et al., 2003). Tooth shape is also different; in Pseudosalix handleyi the teeth are concave on the apical side (Boucher et al., 2003).

Other taxonomic groups that have leaves with morphological similarities to this fossil morphotype include: Fraxinus L. (Oleaceae) which can have an asymmetrical base, but often has a different overall shape than the Blue Rim material and Ziziphus Mill., Sarcomphalus P.

Browne, and Paliurus Mill. (Rhamnaceae) which often have three prominent veins originating near the base, similar to the fossil specimens, but the overall shape is not a match either.

Morphotype—CBT: “Craspedodromous Big Teeth” (Figs. 2-36A-F).

Localities—UF 15761, 15761S, 19225, 19337.

Specimens—UF 15761-48464, 55229, 55230 (?), 53541 (?); UF 15761S-57828, 57829, 61510

(?); UF 19225-51972, 51974 (ls), 51978 (ls), 52029, 52035, 52044, 52048, 54612, 54614, 54616

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(pp), 56996, 56997 (large toothed lobe near base), 56998 (lobe and leaflet), 57001, 57004 (pp);

UF 19337-61583.

Description—Petiolate laminae with marginal attachment. Few specimens compound with two leaflets attached at the same node. Leaflets sessile, microphyllous to mesophyllous. Length to width ratio on five mostly complete specimens averages ~2.1:1. Shape elliptic; laminae medially and often basally asymmetrical. Leaflet displays basal insertion asymmetry; base of most leaves not fully preserved. Laminae range from lobed to unlobed. When lobed, usually palmately and asymmetrical. Margin toothed (serrate). Apex acute and close to straight. Base ranges from acute to obtuse. Base shape on leaves and leaflets varies from convex to decurrent to straight.

Venation pinnate. Naked basal veins absent. Secondaries craspedodromous. Interior secondaries absent; minor secondaries craspedodromous. Perimarginal vein not obvious.

Secondaries slightly irregularly spaced; similar angle of attachment, although secondary course varies slightly from straight with a more acute angle to the midvein to slightly bowed with a larger angle to the midvein. Secondaries with an excurrent attachment to the midvein. Occasional intersecondaries, generally parallel to major secondaries. Length of intersecondaries more than

50% of subjacent secondary; distal course reticulating; less than one per intercostal area.

Tertiaries opposite percurrent where preserved. Epimedial tertiaries percurrent, diverge off primary at ~90°. Higher order venation not preserved.

Teeth somewhat irregularly spaced with two orders. One to two teeth per centimeter; sinuses angular. Tooth shape ST/CV to CV/CV to ST/ST; principal vein present, terminating at the tooth apex.

Discussion—This morphotype ranges from simple and unlobed, to deeply lobed, to compound

(with the lobe becoming a leaflet). Compound teeth, observed in this morphotype, can also be

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taxonomically informative. Similar specimens are preserved at the Barrel Springs site in the

Laney Member of the Green River Formation (also in southwestern Wyoming, but to the east of

Blue Rim).

This morphotype has similarities to taxa in Betulaceae, Ulmaceae, Rosaceae (e.g.,

Crataegus L., Rubus L., Sorbus L., Physocarpus (Cambess.) Raf., Grossulariaceae (Ribes L.), and Sapindaceae (e.g., Koelreuteria Laxm.). Leaves of Betulaceae often have numerous, fine teeth unlike the fossil specimens, but some taxa in Ulmaceae (including species of Zelkova

Spach and Ulmus L.) have larger teeth more similar to the fossil material. Species of Crataegus and some Rubus also often have many small teeth that are closely spaced, which is not true of the

Blue Rim specimens. However, Rubus abbrevians Blanch. has larger and fewer teeth per centimeter, which is more similar to the Blue Rim material. Species of Ribes are quite morphologically variable, but seem to be consistently lobed and more symmetrical than the Blue

Rim specimens. The accepted fossil leaf species of Ribes are also quite different from the Blue

Rim material, so this is an unlikely fit (Hermsen, 2005). The fossils have numerous morphological similarities with Koelreuteria (Sapindaceae) including having very short petioles or sessile leaflets, a similar overall shape, and similar primary and secondary venation characters

(Meyer, 1976). The higher order venation characters are slightly divergent, but they are not completely preserved on the fossil material. Koelreuteria viridifluminis (Hollick) Brown is present in the Green River Formation (MacGinitie, 1969), but it is definitely not the same species as the Blue Rim material. Extant Koelreuteria includes three species native to south and southeastern Asia and are medium sized deciduous trees (Meyer, 1976). The fossil leaves have similarities to K. apiculata Rehder and E.H. Wilson (re-identified as K. paniculata) specimen A

(Arnold Arboretum) 00249536 (viewed on JSTOR Global Plants).

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Morphotype—RL: “Rhus-like” (Figs. 2-37A-G).

Localities—UF 15761, 15761N.

Specimens—UF 15761-55208 (f, pp), 55210 (?, pp, f), 55216, 55217, 55221, 55222, 55234; UF

15761N (2014)-61378 (?).

Description—Petiole not preserved, but laminae marginally attached. Laminae microphyllous, possibly ranging to notophyllous. The length to width ratio on 6 mostly complete specimens averages ~3.2:1 (Range: 2.8:1 to 4.2:1). Shape ovate to elliptic. Medial width symmetric to slightly asymmetrical; base often asymmetrical. Leaves unlobed and toothed. Base and apex often incomplete. Apex acute; base acute to slightly obtuse with a variable shape from cuneate to concave to convex.

Primary venation pinnate. Secondaries craspedodromous to semicraspedodromous.

Excurrent attachment to the midvein. Occasional intersecondaries parallel to major secondaries.

Higher order venation not preserved.

Teeth regularly to irregularly spaced. One order of teeth; two to four teeth per centimeter.

Sinuses angular; tooth shape most commonly ST/ST ranging to slightly CV/CV. Principle vein present, terminating at the margin.

Discussion—Whereas specimens from the upper horizon at Blue Rim match Rhus nigricans

(Lesquereux) Knowlton documented in the Green River Formation (MacGinitie, 1969), these do not appear to be the same taxon. The Green River specimens have more prononunced teeth with longer proximal flanks than the Blue Rim specimens; furthermore, Rhus nigricans is generally longer and narrower in shape than this morphotype (MacGinitie, 1969). However, it is possible that these leaves are also representative of Anacardiaceae. Both wood (Edenoxylon Kruse) and

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fruits (Pentoperculum Manchester) of Anacardiaceae have been confirmed at Blue Rim in the lower horizon.

Some of these specimens have a very asymmetrical base, which suggests that may be leaflets. A few of these specimens (e.g., UF 15761-55208) have similarities to the simple leaves of Cedrelospermum Saporta (Ulmaceae, Manchester, 1989), but the lack of preserved higher order venation on the Blue Rim specimens makes a full comparison challenging. Specimens of

Cedrelospermum are preserved in the upper level at Blue Rim and likely in the lower channel fill

(see Toothed 7).

Morphotype—TT: “Triangle Teeth” (Figs. 2-38A-C).

Localities—UF 19337.

Specimens—UF 19337-61584, 61591.

Description—Marginally attached microphyllous to notophyllous laminae. Length 4.9 cm, width

1.9 cm for a length to width ratio of 2.6:1 (Specimen 19337-61584). Shape ovate to elliptic although only partially preserved. Medially symmetrical. Basal insertion asymmetrical. Laminae unlobed; margin toothed (serrate). Apex not preserved; base slightly obtuse. Shape convex on one side and concavo-convex on the other side. Primary venation pinnate with one basal vein.

Agrophics absent; secondaries semicraspedodromous. Secondaries irregularly to semi-regularly spaced with a uniform angle to the midvein; attachment to the midvein generally excurrent, occasionally decurrent. A few secondaries fork on their course toward the margin.

Intersecondaries present; parallel to major secondaries. Length of intersecondaries more than

50% of subjacent secondary. Intersecondary reticulating and contacting major secondary loop where well-preserved. Less than one intersecondary per intercostal area. Tertiaries mixed percurrent, but not well-preserved. Higher order venation poorly preserved. Teeth regularly to

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irregularly spaced with two orders of teeth, 2-3 teeth per centimeter. Sinuses angular; tooth shape

ST/ST. Principle vein present with marginal termination at the apex of the tooth.

Discussion—These specimens have some similarities to Dipteronia Oliv. the sister genus to Acer

L. (Sapindaceae). However, modern Dipteronia do not have as prominent semicraspedodromous loops as observed in these fossil specimens.

Morphotype—ATR: “Arching Teethy Round” (Figs. 2-39A-C).

Localities—UF 15761, 19225.

Specimens—UF 15761-49826; UF 19225-54602.

Description—Lamina marginally attached and microphyllous. Length 2.3 cm, width 2.4 cm; shape ovate. Medially symmetrical. Base may be slightly asymmetrical in width, but not completely preserved. Lamina unlobed and toothed (serrate). Apex acute, convex; base obtuse to reflex and convex to cordate in shape. Lamina either pinnate with strong basal secondaries or

~palinactinodromous. The exact width of the veins (to see where they fall using the 75% rule,

Ellis et al., 2009) unclear. There appear to be five basal veins. Agrophics present if palinactinodromous. Major secondaries craspedodromous or semicraspedodromous. Minor secondaries (if agrophics) appear craspedodromous. Secondaries semi-regularly spaced; angle to midvein uniform; attachment to midvein generally excurrent, occasionally decurrent.

Intersecondaries not observed. Tertiaries opposite percurrent, close to straight in course. Higher order venation not preserved. One order of teeth present with ~regular spacing. Three to five teeth are preserved per centimeter; sinuses angular. Tooth shape varies from CV/CV to RT/CV.

Principle vein characters not well-preserved in the teeth.

Discussion—The description is based on specimen 19225-54602, as 15761-49826 is not as well- preserved.

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Morphotype—HPT: “Hooked Pointy Teeth” (Figs. 2-40A-B).

Localities—UF 15761.

Specimen—UF 15761-55235.

Description—Laminae marginally attached and notophyllous. Laminae only partially preserved, but appear ovate. Medial symmetry cannot be determined. Base asymmetrical with straight shape on one side and concave on the other. Unlobed, toothed (serrate). Apex not preserved, but likely acute. Base acute. Primary venation pinnate; one basal vein. Secondaries likely semicraspedodromous; they fork near the margin. Secondary spacing and angle consistent where preserved. Secondaries with excurrent attachment to the midvein. Intersecondaries present,

~perpendicular to the midvein, length ~less than 50% of subjacent secondary. Intersecondary distal course ~reticulating/ramifying with ~1 per intercostal area (only a small portion of the leaf well-preserved). Tertiaries irregular/regular reticulate (horizontal polygons with ~6 sides, the top and bottom being long and the ends with 2 shorter sides). Higher order venation reticulate; freely ending veinlets visible. Areolation present, good development. One order of irregularly spaced teeth, ~1 tooth/cm. Sinuses rounded to angular, tooth shape variable from ST/ST to ST/FL.

Discussion—This morphotype, represented by two leaves on the same hand sample, can be distinguished from the other toothed morphotypes in the lower horizon at Blue Rim by its differently shaped spinose teeth. The higher order venation is well-preserved. These leaves have similarities to Quercus L. (Fagaceae) and taxa in Berberidaceae, but the exact taxonomic affinities could not be determined. Quercus leaves have a wide range of morphologies. Some species, Q. acutissima Carruth. for example, lack lobes and have spinose teeth. However, that species has regular percurrent tertiaries, which is not in agreement with the Blue Rim material.

Although many species of Mahonia Nutt.and Berberis L. (Berberidaceae) have spinose teeth in

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common with HPT, other features do not match. Secondaries in these genera are usually brochidodromous or festooned brochidodromous, whereas they are likely semicraspedodromous in the Blue Rim HPT morphotype. In addition the teeth in HPT are smaller and less pronounced than in extant species of Mahonia and Berberis.

Entire-margined Laminae

Morphotype—GB: “Goweria bluerimensis” (Figured in Chapter 5).

Species—Goweria bluerimensis S.E. Allen, Stull, & Manchester

Localities—UF 15761, 15761N, 15761S, 18288?, 19031, 19032, 19225, 19225N, 19337.

Specimens—UF 15761-22732, 48468, 55242, 55243, 55244, 56332 (?, f); UF 15761N (2012)-

57263, 57264, 57271, 57273, 57274, 57275, 57278, 57279 (?, f), 57282, 57638?, 57645; UF

15761N (2014)-43975, 61387, 61496, 61498; UF 15761S (2012)- 57861 (p), 57862, 57864 (?, f),

57865 (?, f), 57876, 57916; UF 18288-58207 (?, nm), 58208 (?, ss); UF 19031-39016, 39022,

39024; UF 19032-38989, 38991, 38992, 38996, 38997, 39001, 39006, 39013,; UF 19225-56969,

56970, 56971, 56974 (?, f), 56980, 57003 (f), 57032 (?, f), 57040, 57208, 59495; UF 19225N-

57958; UF 19337-58078.

Description & Discussion—See Chapter 5

Morphotype—TCE: “True Cedrela Entire” (Figs. 2-41A-F).

Species—Cedrela schimperi (Lesquereux) MacGinitie.

Localities—UF 19225, 19337.

Specimens—UF 19225-56938 (?, c, pp), 56939, 56943 (?, c), 56966 (?), 56988, 56990 (?, c, pp),

56991, 57009, 57029 (f), 57034, 57035, 57036, 57094, 57110 (?), 57112, 59496 (?, c, pp); UF

19337-58044.

Description—Leaves (leaflets) are petiolate although petiole often not preserved and/or quite short. (Leaves are once pinnately compound, but compound specimens are rare). Leaflets

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microphyllous to mesophyllous. Length to width ratio averaged to 3.2:1 from six mostly complete specimens. Shape elliptic with the broadest part of the leaf often ~1/3 distance from the base to the apex of the lamina. The margins on some specimens nearly parallel. Medial width symmetric to slightly asymmetrical. Base symmetrical to asymmetrical. Basal width asymmetry frequent, occasional slight basal insertion asymmetry. Leaflets unlobed and untoothed. Apex acute and straight, some specimens with a slightly acuminate apex on one side. Base obtuse, varying from close to 90° to significantly broader. Base shape variable from rounded to convex to convex on one side and straight on the other side.

Primary venation pinnate with one basal vein. Agrophics absent. Major secondaries brochidodromous. Interior secondaries absent. Fimbrial vein not observed. Major secondaries regularly spaced; with close to uniform angle from midvein (average 62.7° from 12 specimens).

The secondaries near the base of the leaf diverge at higher angles than in the mid and upper portions of the leaf—partially matching the character of secondary angle smoothly increasing proximally. Major secondaries with excurrent attachment to the midvein. Intersecondaries not obvious. Higher order venation not well-preserved (visible in patches on specimens 19225-57112 and 19225-56991). Tertiaries appear irregular reticulate. Epimedial tertiaries contact midvein at

~90 degrees. Quaternary or quinternary? (both?) venation irregular reticulate, areoles are present with good development. Freely ending veinlets present, branched.

Discussion—These specimens match those that MacGinitie (1974) assigned to Cedrela schimperi (Meliaceae) in his treatment of the Kisinger Lakes flora. Additional specimens of the same species have been recovered from the Kisinger Lakes site more recently (e.g., UF 19376-

60076). Specimen UF 19376-60076 preserves the pinnately compound organization of the leaves. The Kisinger Lakes specimens are better preserved than the Blue Rim material. They

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have slightly irregular secondary angles and spacing. The secondaries diverge at ~80° near the base of the leaflets and at ~60° in the middle of the leaf, which is consistent with the Blue Rim material. The secondaries arch upwards toward the margin and intersecondaries are common.

The leaf architecture of these fossil specimens is consistent with that observed in the modern genus Cedrela; however, indistinguishable leaves are also found in other sapindalean genera and none of the distinctive winged seeds of Cedrela have been found at Blue Rim or Kisinger Lakes.

Specimens of this morphotype have also been recovered from ~56 Ma quarries from the

Bighorn Basin of northcentral Wyoming (S. Manchester and S. Wing, personal communication,

2016). Both in the Bighorn Basin and at Blue Rim these leaves are found in association with fruits of an extinct sapindalean genus, Landeenia (Manchester and Hermsen, 2000). The UF

19225 quarry at Blue Rim also preserves flowers and seeds of Landeenia aralioides

(MacGinitie) Manchester and Hermsen. Based on their co-occurrence, it is possible that the

Cedrela schimperi leaflets and the reproductive material of Landeenia aralioides represent a single extinct taxon.

This morphotype is similar to specimens assigned to the VCT morphotype, also in the lower horizon of Blue Rim. The TCE specimens differ in that they lack teeth and usually have more rounded, symmetrical bases. Furthermore, secondaries in this morphotype, TCE, are more regularly spaced than in VCT. A few specimens assigned to TCE (e.g., 19225-57110; 19225-

56966) are similar to the legume morphotype from the upper horizon. They have a rounded, symmetrical base; however, none of these specimens have a well-preserved petiole to ascertain whether a pulvinus is present. The venation, size, and shape otherwise matches with TCE.

Morphotype—TRB: “Teardrop Rounded Base” (Figs. 2-42A-C).

Localities—UF 15761, 15761S.

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Specimens—UF 15761-55186, 55187; UF 15761S-57840.

Description—Marginally attached petiolate (petiole ~1.3 mm wide by 1.7 cm long on specimen

15761-55187) leaves microphyllous (15761-55187 likely on border with notophyllous). Length

4.2 cm; width 1.4 cm for a length to width ratio of 3:1 (15761-55186). Specimen 15761S-57840

4.6 cm long (incomplete) by 1.9 cm wide for a length to width ratio of 2.4:1. Length not preserved on specimen 15761-55187, but width 2.5 cm. Shape elliptic to ovate. Medial width symmetric to just slightly asymmetrical. Base symmetry variable from asymmetric in width to slight insertion asymmetry. Leaves unlobed and untoothed. Apex acute and straight to occasionally convex; base obtuse or close to 90° and convex to rounded in shape. Venation pinnate, primary vein stout; one basal vein. Agrophics absent. Major secondaries interaction with the margin not clear, likely brochidodromous to eucamptodromous. Interior secondaries absent; perimarginal vein not observed. Secondaries irregularly and distantly spaced except for a few closer veins near the base. Secondary angle to midvein ~uniform to abruptly increasing proximally. Secondaries with excurrent attachment to the midvein. Intersecondaries present; parallel to major secondaries. Intersecondary length less than 50% of subjacent secondary; distal course not clear on some specimens, reticulating or ramifying on others. Frequency of intersecondaries less than one per intercostal area ranging to approximately one per intercostal area. Tertiaries ~irregular reticulate. Higher order venation not well-preserved. Freely ending veinlets ~present.

Discussion—Morphotype TRB can be distinguished from others in the lower horizon by its rounded to convex base and irregular, widely spaced secondaries.

Morphotype—BTBP: “Big Tropical Blue/Pink” (Figs. 2-43A-E).

Localities—UF 15761, 15761N, 15761S, 19337.

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Specimens—UF 15761-55189, 55192; UF 15761N (2012)-57640, 57654, 57655, 57656, 57659,

57660, 57661, 57664, 57665, 57666, 57669; UF 15761N (2014)-43945, 43948, 43995 (18),

61375 (310), 61383 (199), 61393, 61419 (226), 61421 (221), 61423, 61465 (153), 61470, 61477,

61482, 61491 (179), 61495 (131); UF 15761S (2012)-57832, 57835 (?, pp), 57837 (pp), 57839

(f, p), 57841, 57843, 57872 (HOV wp), 57873; UF 19337-61528.

Description—Petiolate, marginally attached, microphyllous to mesophyllous leaves. Petiole can be over 3 cm long and 2 to 3 mm wide. Length to width ratio from three specimens (very few specimens with both base and apex preserved) averaged to 2.1:1 (Range: 1.8:1 to 2.4:1). Shape varies from elliptic to ovate. Symmetry variable from symmetric to asymmetric. Leaves unlobed and untoothed with an acute, straight to acuminate apex. Base obtuse to reflex and the shape varies from truncate, to convex, to rounded, to concavo-convex.

Primary venation pinnate; primary thick. Naked basal veins present; 2-3 basal veins. No agrophics or interior secondaries. Fimbrial vein present. Secondaries brochidodromous, occasionally forking en route to the margin. Secondary spacing regular to irregular to smoothly and gradually increasing proximally. Secondary angle uniform, often ~90° or slightly less or with the basal pair of secondaries ~90° and the others more acute. Secondary attachment to midvein excurrent, occasionally decurrent near base. Intersecondaries present; perpendicular to midvein or parallel to major secondaries (which also diverge at ~90° in many cases).

Intersecondary length variable from less than 50% of subjacent secondary to slightly greater than

50% of subjacent secondary. Distal course of intersecondary perpendicular to a subjacent major secondary. Less than one intersecondary per intercostal area ranging to 1-2 per intercostal area.

Tertiaries mixed to alternate percurrent with occasional irregular reticulate. Epimedial tertiaries reticulate; exterior tertiaries looped. Fourth and fifth order venation irregular reticulate. Areoles

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present with good development. Mesh closed and orthogonal. Freely ending veinlets present; two or more branched, likely dichotomous. Marginal ultimate venation looped.

Discussion—Morphotype BTBP can be distinguished from the two other BT morphotypes by its attenuate apex and obtuse base that is truncate to slightly cordate in shape. The secondaries loop very close to the margin and taper in the basal portion of the leaf. Intersecondaries are present, unlike BTY. The higher order venation is well organized.

The taxonomic affinity of this morphotype is unknown, but it has some similarities to

Ficus ungeri Lesquereux (Berry, 1930). However, F.ungeri has more in common with BTY than this morphotype. Some of the pinnate taxa of Menispermaceae have a fine orthogonal mesh and a fimbrial vein like this morphotype. Morphotype BTBP also has similarities to some taxa in

Lauraceae and Magnoliaceae.

Morphotype—BTY: “Big Tropical Yellow” (Figs. 2-44A-D).

Localities—UF 15761, 15761N.

Specimens—UF 15761-55200; UF 15761N (2012)-57657 (?); UF 15761N (2014)-43996 (40,

24), 61417.

Description—Marginally attached petiolate leaves; mesophyllous to at least macrophyllous.

Length to width ratio from two specimens averages to ~2.0:1. Shape likely elliptic. Leaves untoothed and unlobed. Apex rarely preserved, but acute and straight on specimen 15761N-

57657. Base angle acute to obtuse to reflex, cuneate to cordate in shape.

Primary venation pinnate. Agrophics absent. Secondaries brochidodromous; interior secondaries absent. Secondaries occasionally branch near margin with tertiaries forming the end of the loop. No clear perimarginal vein preserved, margin has looping tertiaries and higher order venation. Secondary spacing somewhat irregular to regular. Secondaries with a uniform angle

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and excurrent attachment to the midvein. Intersecondaries absent. Tertiaries mixed percurrent with a straight to sinuous course. Angle of tertiaries to midvein obtuse. Epimedial tertiaries mixed percurrent, mostly opposite and perpendicular to the midvein. Distal course of epimedial tertiaries basiflexed to parallel to the intercostal tertiaries (bend down toward the base of the leaf). Exterior tertiaries looped. Quaternaries alternate percurrent to semi-regular reticulate.

Quinternaries semi-regular reticulate. Areolation present, good development. Freely ending veinlets present; looks like mostly with two or more branches—likely dichotomous. Marginal ultimate venation looped.

Discussion—This morphotype lacks intersecondaries unlike BTBP and BTOS. The tertiaries are prominent and generally opposite percurrent, while they are more alternate to irregular in BTBP.

The tertiaries also form distinctive loops in the base of this morphotype, which was not observed in the other BT morphotypes.

Morphotype BTY has similarities to specimens of Ficus ungeri Lesquereux (Berry,

1930). Like BTY, Ficus ungeri lacks intersecondaries and has tertiaries with a generally straight course. The base shape is also similar. However, F. ungeri differs from BTY in that the secondaries are eucamptodromous in most of the leaf except at the very top of the apex where they transition to brochidodromous (Berry, 1930). The secondaries in BTY are brochidodromous throughout the lamina.

Morphotype—BTOS: “Big Tropical Orange Star” (Figs. 2-45A-C).

Localities—UF 15761N.

Specimen—UF 15761N-61420.

Description—Lamina marginally attached. Petiole at least 1.5 cm long and ~2 mm wide near its attachment to the lamina, but it tapers away from the leaf blade. Notophyllous with an

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incomplete length of 7.8 cm, width 3.5 cm for a length to width ratio of ~2.2:1. Shape elliptic.

Medial width asymmetrical 1.6 vs. 1.9 cm. Base relatively symmetrical. Leaf unlobed and untoothed. Apex acute, straight to convex. Base acute, straight to convex.

Primary venation pinnate. Lowest part of the base obscured. Agrophics absent. Major secondaries brochidodromous. Interior secondaries absent. Major secondary spacing irregular.

Secondary angle smoothly increasing proximally (very minor change). Major secondaries with excurrent attachment to the midvein. Intersecondaries present, close to perpendicular to midvein, more than 50% of subjacent secondary. Intersecondary distal course basiflexed and not joining the subjacent secondary at right angles. Frequency of intersecondaries less than one per intercostal area. Tertiaries mixed percurrent. Obtuse tertiary angle. Intercostal tertiary vein angle variability unknown because they cannot be distinguished on all parts of the leaf. Quaternaries and quinternaries irregular reticulate. Areoles present, good development. Freely ending veinlets present, mostly with two or more branches. FEV terminals with likely tracheoid idoblasts.

Discussion—Morphotype BTOS has a more acute base than most of the specimens assigned to

BTBP or BTY.

Morphotype—SYZ: “Syzygioides” (Figs. 2-46A-G).

Species—Syzygioides americana (Lesquereux) Manchester, Dilcher et Wing.

Localities—UF 15761, 18289, 19337.

Specimens—UF 15761-48619, 55177, 55245, 55246, 55247, 55248, 55249, 55250, 55251,

55252; UF 18289-56297; UF 19337-58080.

Description—Leaves petiolate with marginal attachment, microphyllous. The length to width ratio of 5 mostly complete specimens averaged to 5:5:1 (Range: 5.0:1 to 6.0:1). Laminar shape elliptic, but leaf shape very long and thin. Medial width variable from symmetric to asymmetric;

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base with slight basal insertion asymmetry. Leaves unlobed and untoothed. Apex acute, rarely preserved. Base acute and cuneate. Primary venation pinnate; primary thick and prominent.

Intramarginal secondary present; major secondaries meet intramarginal secondary. Secondary spacing somewhat irregular and increasing proximally. First few secondaries near base often with larger angle of divergence than most secondaries in the lamina which have a generally uniform angle. Secondaries with either an excurrent or decurrent attachment to the midvein.

Intersecondaries present; ~parallel to major secondaries, more than 50% of subjacent secondary, perpendicular to subjacent major secondary, less than one per intercostal area. Tertiaries opposite percurrent with an irregular course and ~perpendicular to midvein. Higher order venation not well-preserved.

Discussion—This morphotype matches the extinct taxon Syzygioides americana known also from specimens showing opposite phyllotaxy and attached fruits (Manchester et al., 1998).

Syzygioides is an extinct genus in the Myrtaceae. The intramarginal secondary is distinctive and aids in the recognition of this leaf type. Intersecondaries are also common. Manchester et al.

(1998) also provide a full description of leaves of this species from the Green River Formation.

Morphotype—SYM: “Symplocos” (Figs. 2-47A-D).

Species—Symplocos incondita MacGinitie.

Localities—UF 19032.

Specimens—UF 19032-39008, 39014.

Description—Leaves marginally attached, microphyllous to notophyllous. Shape elliptic to obovate; medial width asymmetrical. Leaves unlobed, untoothed. Neither apex nor base preserved on specimen 19032-39008. Apex acute and straight on one side and acuminate on the other; base acute and cuneate on specimen 19032-39014.

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Primary venation pinnate (~1 mm wide on specimen 19032-39014); agrophics absent.

Secondaries festooned brochidodromous; irregularly spaced, angle of divergence from the midvein similar. Secondaries with decurrent or excurrent attachment. Intersecondaries present, generally parallel to major secondaries, length ~slightly less than subjacent secondary, distal course of intersecondary approximately perpendicular to subjacent major secondary.

Intersecondary frequency varies from less than one per intercostal area to approximately 1 per intercostal area (features of intersecondaries hard to determine because the venation very irregular). Tertiaries and higher order venation irregular reticulate. Freely ending veinlets visible; areolation present.

Discussion—These specimens match those assigned to Symplocos incondita (Symplocaceae;

Ericales) from the Kisinger Lakes site in northwestern Wyoming (MacGinitie, 1974).

Summary of Lower Horizon Leaves

The lower horizon at Blue Rim preserves twenty dicotyledonous angiosperm morphotypes (12 toothed and 8 untoothed). Certain taxa are usually well-preserved with higher order venation visible (e.g., “Aleurites” fremontensis), whereas higher order venation is rarely preserved in others (e.g., Serjania rara). This may be due, in part, to original differences in leaf thickness, with veins more buried within the mesophyll in some taxa than others. All of the lower level quarries being more or less along strike, but scattered over ~2.4 km (most <1 km), were considered together in this floristic inventory because the diversity from individual quarries is quite low. This suggests a heterogeneous landscape, with ten morphotypes only represented at one quarry (9 quarries included). In contrast, seven of the 20 morphotypes were documented from at least three quarries. This heterogeneity suggests regular microenvironments or habitats.

This may be due to different moisture regimes across the landscape with plants dropping their

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organs very close to where they grew rather than being carried and mixed together as might occur in a large lake deposit, for example.

In general, the most common dicotyledonous morphotype at the lower level is Populus cinnamomoides. This comprised ~38% (143 of 375 leaves) of specimens in an unbiased field census (quarry UF 15761N on 7/5/2014). This site is one of the more diverse lower level quarries with representatives of 17 of the 20 leaf morphotypes. The count encompassed approximately

1.49 m3 of rock. Monocots (e.g., 15761-56329) are rare in the lower horizon. Specimens with affinities to Araceae (e.g., 19225-56981, 56984), identified by S.Y. Smith, and occasional palm foliage fragments (e.g., 15761-56328) have been recovered. Ferns include rare Acrostichum hesperium Newberry (e.g., 19225-51988, 15761-48573). The non-angiosperm taxa are dominated by the climbing fern Lygodium kaulfussi (e.g., 19338-61875); 2881 specimens of

Lygodium kaulfussi were counted from a single quarry (UF 19225, 6/9-6/11/2016). The census at this same quarry recovered 812 dicotyledonous leaves or leaf fragments and no monocots. The dicotyledonous taxa recovered from this quarry included specimens with affinities to Serjania rara, cf. Rhus, Goweria bluerimensis, Populus sp., and Cedrela schimperi. This count encompassed approximately 1.28 m3 of rock.

At least six of the leaf morphotypes from the lower horizon (including: SR, AF, PC,

TCE, SYZ, & SYM) are shared with the regional flora (Kisinger Lakes and Green River).

Part III: Leaf Morphotypes from the Upper Horizon

In this section I treat the leaves recovered from the upper horizon quarries including specimens recovered from four quarries, i.e., UF 00341, 19296, 19297, and 19405. The first 21 morphotypes are serrate dicotyledonous leaves, grouped together under “toothed” the remaining

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15 leaf types are grouped under “untoothed.” This is followed by a list of monocot and fern foliage recovered from the upper horizon.

Toothed Morphotypes

Morphotype—“DE” (Figs. 2-48A-J).

Specimens—UF 00341-61867 (f), UF 19296-43811 (24, p, f), 43833 (54), 54635, 58230 (9, ?, f, pp), 58237 (?, f), 58261(16, ?, pp);UF 19297-43660 (53), 43683 (105), 43690 (103, ?), 43692,

43693 (153), 43709 (179), 43716 (195), 43719 (174), 43743 (107), 43744 (74, ?, pp, f), 43769

(214), 43771 (202), 43787 (51), 43791 (142), 43892, 43894 (22, pp), 43912 (8), 54206 (?, pp),

54223 (p), 54233 (f), 54299 (?, f), 54303 (?, f), 54305 (ss), 54317 (p), 54321, 54347 (?, pp, ls),

54349 (p), 54697 (p), 58100 (9), 58102 (51, p?), 58129 (43), 58161 (68, ss), 58172 (?, pp),

58178 (50, f), 58183 (7, ?, p, pp), 69733 (52, ?); UF 19405-61634 (?, p), 61636 (?, f), 61637,

61646 (?), 61657.

Description—Petiolate (petiole >1.5 cm long on 19296-43811), marginally attached laminae microphyllous to notophyllous. Laminae often incomplete, but few nearly intact specimens as follows: 4.3 cm long by 1.5 cm wide for a length to width ratio of 2.9:1 (19297-43719); length

7.6 cm, estimated width ~3.3 cm for a length to width ratio of 2.3:1 (19297-58129); length ~7.6 cm, width ~3.1 cm for a length to width ratio of 2.5:1 (19297-58100). Laminar shape ovate to elliptic. Medial and basal symmetry often asymmetrical in width, but ranges to symmetrical especially on specimens with an acute base. Laminae unlobed and toothed (serrate). Apex acute, straight to acuminate, and without teeth. Base obtuse, close to 90°, or acute. Base shape often different on each side due to the asymmetry and ranges from straight to convex to slightly concave. Alternatively, base cuneate on both sides (e.g., 19297-43787, 54321, 54697).

Venation pinnate. One basal vein present; naked basal veins absent. Agrophics absent.

Major secondaries semicraspedodromous, but appear to transition to brochidodromous in the

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entire apical tip. Interior secondaries absent; fimbrial vein present. Major secondaries with regular to slightly irregular spacing. Major secondary angle to the midvein close to uniform on some specimens and more inconsistent on others. Secondaries with excurrent attachment to the midvein. Intersecondaries present, perpendicular to midvein, length slightly longer or slightly shorter than 50% of subjacent secondary, intersecondary distal course perpendicular to subjacent major secondary. Intersecondary frequency less than one per intercostal area. Tertiaries mixed percurrent with an obtuse angle to the midvein. Exterior tertiaries looped. Quaternaries irregular reticulate. Higher order venation not preserved.

One to rarely two orders (e.g., 19297-54321) of regularly spaced teeth; three to six (rarely up to 8/cm on smaller specimens, e.g., 19297-58161) teeth per centimeter. Sinuses angular.

Tooth shape variable from CV/CV to ST/CV to ST/ST. Principle vein present, terminates at

~apex of the tooth. Occasionally teeth more rounded and bulbous (e.g., 19297-54299, 54347).

Discussion—This morphotype, DE, is likely representative of a compound leaf. The majority of specimens have obtuse, asymmetrical bases (likely representative of lateral leaflets), but some specimens with the same venation and teeth have acute, straight, symmetrical bases (likely representative of the terminal leaflets). These features, in addition to the percurrent tertiaries, are similar to some extant Juglandaceae. Pollen of Juglandaceae, (e.g., cf. Carya) is common at Blue

Rim in the upper horizon (see Chapter 3). Similar leaflets are also present in the slightly younger

Clarno Formation (Oregon).

Morphotype—“MAC” (Figs. 2-49A-D).

Species—Macginitiea wyomingensis (Knowlton and Cockerell) Manchester.

Specimens—UF 19296-43812 (9), 43813 (49), 43832 (10), 43847 (68), 43866, 54620, 54621,

54624 (p), 54640, 54653 (f), 54656 (?, f), 54658 (f), 58231 (p), 58235 (f), 58251, 58263 (p); UF

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19297-43663 (60, ?), 43665 (32), 43698 (160), 43734 (76), 43737 (70), 43750 (f, nm), 43757

(137),43761 (116), 43767 (185), 43782 (210), 43795 (141, ?), 54208, 54210 (f, HOV wp), 54228

(f), 54300, 54309 (f), 54317 (?, pp, f), 54320 (f, pp), 54344 (f), 58112 (66, f, HOV wp), 58132

(25), 58165 (98, ?, f), 58179, 58181 (80).

Description—Marginally attached leaves mesophyllous to macrophyllous. Length at least 7 cm; width at least 7 cm (19297-54208). Shape ~elliptic. Laminae symmetrical, lobed, and toothed.

Leaves with 5 lobes observed at Blue Rim. Apex acute and straight. Base obtuse and ~straight.

Venation palinactinodromous. Secondaries semicraspedodromous. Marginal secondary present.

Intersecondaries present, vary between parallel to major secondaries and perpendicular to midvein. Intersecondaries more than 50% of subjacent secondary. Intersecondary distal course variable from reticulating or ramifying to bending either apically or basally to meet the adjacent secondary with a perpendicular angle. Frequency less than one per intercostal area to usually one per intercostal area. Tertiaries mixed percurrent to irregular/regular reticulate. Quaternaries and quinternaries irregular to regular reticulate. Areolation present; good development. Freely ending veinlets present, branched, possible tracheoid idioblasts on terminals.

Teeth concentrated on the apical tips of the lobes and regularly spaced in that area. One order of teeth observed with 2-4 teeth/cm. Sinuses rounded. Teeth pointy to spiny and CC/ST to

CC/CV to CC/RT in shape.

Discussion—Most specimens of Macginitiea wyomingensis from Blue Rim are incomplete.

Multiple specimens have evidence of insect hole feeding. This species is also preserved in the

Aycross (northwestern Wyoming) and Green River Formations (MacGinitie, 1969; MacGinitie,

1974); it was originally documented as Platanus before being transferred to the extinct platanaceous genus Macginitiea (Manchester, 1986; Wolfe and Wehr, 1987). Here, as at other

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localities where Macginitiea is found, are the associated globose infructescences of

Macginicarpa which were likely produced by the same plant (see Chapter 3).

Morphotype—PL: “Platanus-like” (Figs. 2-50A-D).

Species—Platanus sp.

Specimens—UF 00341-61871 (?, p, f); UF 19296-43828 (23, ?, f), 58240 (10, ?, f); UF 19297-

43676 (62), 43682 (69, ?), 43698 (159), 43708 (180), 43724 (212), 43728 (194), 43748 (140, ?),

43765 (171), 43766, 43773 (207), 43897, 43909 (7), 43910 (1), 54232 (?, f), 54320 (?, pp, p),

58114 (?, f, HOV pp), 58120 (46), 58126 (39, p), 58182 (f).

Description—Marginally attached petiolate leaves range from microphyllous to mesophyllous.

Petiole just over 1 mm wide and ~12 mm long (19297-58126). Length to width ratios vary: 8.9 cm long by 9.5 cm wide for a ratio of 0.94:1 (19297-43676), 4.7 cm by 4.8 cm for a ratio of

0.98:1 (19297-43910), 2.4 cm long by 1.4 cm wide for a ratio of 1.71:1 (19297-43728), and 6 cm long by ~4 cm wide for a ratio of 1.5:1 (19297-58126). Shape elliptic to ovate. When preserved, laminae medially and basally symmetric. Leaves range from lobed to unlobed; if lobed palmately lobed. Margin toothed (serrate). Apex acute and straight. Base acute and straight (e.g., 19297-

43728) to obtuse and straight to convex to slightly concavo-convex (e.g., 19297-43676, 43910).

Primary venation pinnate if unlobed, palinactinodromous if lobed. Naked basal veins present. Agrophics present, vary from simple to compound. Major secondaries variable from craspedodromous when teeth frequent to semicraspedodromous when teeth rare. Interior secondaries absent. Minor secondaries craspedodromous to semicraspedodromous. Marginal secondary present. Secondary spacing regular to slightly irregular (e.g., decreasing proximally,

19297-58126). Secondary angle to the midvein uniform to abruptly increasing proximally. Major secondaries with excurrent attachment to the midvein. Intersecondaries present (e.g., 19297-

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58120, 58126), intermediate between parallel to major secondaries and perpendicular to midvein.

Intersecondary less than 50% of subjacent secondary; distal course perpendicular to a subjacent major secondary. Intersecondary frequency less than one per intercostal area. Tertiaries mixed percurrent, opposite more common. Tertiaries form a slightly acute or perpendicular angle to the midvein along the primary, but are obtuse away from the primary. Overall, tertiary angle increases exmedially. Epimedial tertiaries mixed percurrent with opposite more frequent, course approximately perpendicular to the midvein. Distal course of the epimedial tertiaries parallel to intercostal tertiaries. Exterior tertiaries looped. Quaternaries irregular reticulate, quinternaries irregular to regular reticulate. Areolation present, likely with moderate to good development, but rarely preserved.

Teeth regularly spaced, when present; one order. Number of teeth per centimeter variable from none on large specimens, when the teeth are very widely spaced, to up to 4 teeth per centimeter. Sinuses rounded; tooth shape CC/CV, CC/ST to CC/CC. Principle vein present, terminating at the tooth apex. Major accessory veins include the marginal secondary; its course follows the shape of the tooth. Tooth apex possibly cassidate.

Discussion—These specimens range from lobed to unlobed with a large variation in size. These differences likely represent the morphological variation between juvenile, mature, stump sprout, and crown leaves on extant Platanus. Some of these specimens also resemble leaves of Vitaceae.

Fruits and seeds of Vitaceae are present in the lower horizon at Blue Rim, so this affinity is possible. Some of the PL specimens also resemble Distylium eocenica (Brown) MacGinitie from the Green River flora (MacGinitie, 1969).

Morphotype—CN: “Cedrelospermum nervosum” (Figs. 2-51A-D).

Species—Cedrelospermum nervosum (Newberry) Manchester.

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Specimens—UF 19296-43821 (33, p), 58234 (?, nm, f); UF 19297-42781 (181), 43677 (100, nm), 43717 (pp), 43735 (106, ?, nm, f), 43756 (f), 43898 (17), 43905 (?, nm, f), 54222, 54235,

54306 (?, nm, ss).

Description—Marginally attached leaves with petiolate attachment. Preserved petiole is ~0.75 mm wide by 3.5 mm long (19297-54235). Leaves microphyllous with an elliptic shape.

Incomplete length 3.6 cm, width 1.7 for a length to width ratio 2.1: 1 (19297-54222). Leaves medially symmetrical with a slight basal asymmetry in width. Leaves unlobed and toothed

(serrate). Apex and base acute and straight. Primary venation pinnate; secondaries craspedodromous. Naked basal veins absent; one basal vein present. Agrophics and interior secondaries absent. Perimarginal vein absent. Secondaries regularly spaced and angled with excurrent attachment. Intersecondaries absent. Tertiaries mixed percurrent with an obtuse angle to the midvein. Irregular reticulate quaternaries and quinternaries. Areoles present; good development. Freely ending veinlets present. One order of regularly spaced teeth. Sinuses angular. Three to five teeth per centimeter. Tooth shape ST/ST to ST/CV. Principle vein present, terminates at the distal flank or tooth apex even though it comes into the lower half of the tooth.

Discussion—These specimens are easily recognized by their generally small size, very regularly spaced and angled secondaries, and well-organized mixed percurrent tertiaries. Cedrelospermum nervosum is also found at Kisinger Lakes and in the Green River Formation; MacGinitie recognized these leaves as ulmaceous, but assigned them to the extant genus Zelkova as Zelkova nervosa (Newberry) Brown (MacGinitie, 1969; MacGinitie, 1974). These leaves were later transferred to Cedrelospermum nervosum (Newberry) Manchester when they were found attached to twigs bearing fruits of the extinct ulmaceous genus Cedrelospermum Saporta

(Manchester, 1989).

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Morphotype—RN: “Rhus nigricans” (Figs. 2-52A-G).

Species—Rhus nigricans (Lesquereux) Knowlton.

Specimens—UF 19296-43804 (26), 43816 (22, p), 54625 (p); UF 19297-43688 (75), 43725

(167), 43738 (72), 43742 (101), 43796 (139), 54234, 54327 (?, pp), 58136 (53, ?, p).

Description—Marginally attached, petiolate laminae, microphyllous. Incomplete length 6 cm, width 2.3 cm (19297-54234), 6.2 cm by 1.9 cm (19297-43738). Shape ovate to elliptic. Medially symmetric, base asymmetrical in width (19297-43742; missing on most specimens). Unlobed, toothed (serrate) lamina. Apex acute and straight; base acute and straight to slightly convex.

Venation pinnate, primary stout; secondaries craspedodromous with excurrent attachment to the midvein. Secondaries regularly and closely spaced and angled with a straight course.

Intersecondaries present; frequent, but faint. Intersecondaries appear parallel to the major secondaries. Higher order venation not preserved.

Teeth regularly spaced where visible. One to rarely two orders of teeth; 2-3 teeth per centimeter. Sinuses angular. Tooth shape varies from ST/ST to CC/CV to CV/CV.

Discussion—These specimens have more features in common with extant Rhus than the Rhus- like specimens from the lower horizon. Rhus nigricans has also been recognized from the Green

River Formation (MacGinitie, 1969).

Morphotype—AT: “Aleurites type” (Figs. 2-53A-C).

Species—“Aleurites” sp.

Specimens—UF 19296-43805 (70, ?, p), 43831 (41, ?, nm); UF 19297-43689 (f, pp), 43754

(136, f, pp), 54230 (p), 58141 (75, p), 58163 (83, ?, f).

Description—Marginally attached laminae. Partially preserved petiole ~1.5 mm wide (19297-

54230). Laminae mesophyllous. Width of specimen 19297-54230 7.3 cm, length not preserved.

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Laminae symmetrical. Laminae lobed (incisions 27.7% of distance to midvein, just surpassing the cutoff to be lobes rather than teeth) and toothed (serrate). Venation pinnate; 3-5 basal veins.

Presence/absence of agrophics unclear due to the fragmentary nature of the specimens.

Secondaries craspedodromous in limited area visible. Interior secondaries absent. Thin marginal secondary present. Secondaries with excurrent attachment to the midvein. Intersecondaries not observed. Tertiaries mixed percurrent, opposite more common. Angle of percurrent tertiaries opposite. Epimedial tertiaries just slightly acute to midvein. Exterior tertiaries looped.

Quaternary venation irregular reticulate. Details of higher order venation not preserved. One order of irregularly spaced teeth with a very slightly rounded sinuses. Four to five teeth per centimeter when present. Teeth ST/ST in shape. Principle vein present in teeth, terminates at the tooth apex.

Discussion—Most of the AT specimens are small fragments with few characters, but they have the “dots” characteristic of other “Aleurites” specimens at Blue Rim. However, the dots are not as obvious on these as compared to the specimens from the lower horizon. Some of these specimens have been labeled as Platanus (e.g., 19297-58141), but they look like specimens previously called Aleurites, including “Aleurites” glandulosa (Brown) MacGinitie as figured on

Plate 25 (MacGinitie, 1969). In general, these specimens are more similar to “Aleurties” glandulosa found in the Green River Formation than “Aleurites” fremontensis from the Kisinger

Lakes site in northwestern Wyoming (MacGinitie, 1969; MacGinitie, 1974).

Morphotype—SR-U: “Serjania rara-upper” (Figs. 2-54A-C).

Species—Serjania rara MacGinitie.

Specimens—UF 19296-43866 (?, f), 54647, 58267 (11, ?, pp, f); UF 19297-43680 (92, ?), 43763

(119), 43890 (13, ?, pp), 43904 (19).

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Description—Petiolate leaves with marginal attachment. Laminae microphyllous. Length 3.5 cm by 1.8 cm wide (19297-43763). Shape ovate. Medially and basally asymmetrical in width

(19297-43763) to symmetrical (19297-43904). Laminae lobed (single lobe in 19297-43763) to unlobed (teeth are right on the margin of being considered lobes); margin toothed. Apex acute.

Base obtuse (19297-43763) to acute (19297-43904); shape convex to cuneate. Primary venation pinnate. Secondaries craspedodromous. Higher order venation not preserved. Teeth irregularly spaced; two orders. One to two teeth per centimeter with angular sinuses. Tooth shape CV/CV.

Principle vein present.

Discussion—This species is much less common in the upper level than the lower level.

Morphotype—MLA: “Mac look alike” (Figs. 2-55A-D).

Specimen—UF 19297-43732 (104), 54345 (?, f).

Description—Marginally attached lamina, mesophyllous. Length ~16.5 cm, width ~4.2 cm for a length to width ratio of 3.9:1. Shape ovate to elliptic. Lamina medially and basally asymmetric.

Lamina unlobed and toothed. Apex acute and appears straight; base obtuse and straight to convex. Venation pinnate; at least some secondaries craspedodromous, but the margin not completely preserved. Major secondaries regularly spaced and angled with excurrent attachment.

Possible, rare intersecondaries, but preservation unclear. (In specimen 19297-54345 intersecondaries present; more than 50% the length of subjacent secondary, distal course perpendicular to subjacent secondary). Fourth order venation irregular reticulate where preserved. One order of regularly spaced teeth. One to two teeth per centimeter; sinuses angular.

Tooth shape variable from ST/ST to ST/CV to CV/CV.

Discussion—Although the MLA specimens look like a lobe of Macginitiea at first glance, they are distinct. Specimen 19297-43732 has a complete margin around the base and the tooth sinuses

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are angular rather than rounded as in Macginitiea. This specimen has similarities to Fagaceae including Quercus and Castanea.

Morphotype—PC-U: “Populus cinnamomoides-upper” (Figs. 2-56A-C).

Species—Populus cinnamomoides (Lesquereux) MacGinitie.

Specimens—UF 19297-43718 (198), 43768 (193), 58105 (34, f).

Description—See description in Manchester et al. (2006) or from the lower horizon.

Discussion—None of these specimens are particularly well-preserved.

Morphotype—CS: “cf. Salix” (Figs. 2-57A-F).

Species—cf. Salix sp. / cf. Pseudosalix sp.

Specimens—UF 00341-58301; UF 19296- 54623, 54650 (?, pp); UF 19297-43672 (50, pp),

43674 (29, pp), 43758 (124, pp), 43772 (209, pp), 43895 (pp).

Description—Laminae marginally attached, petiolate and microphyllous to notophyllous. Petiole

2 cm long, ~1 mm wide (00341-58301). Shape linear to elliptic, width variable (0.7 cm, 19297-

43772; ~1.2 cm, 19297-43895; 2.9 cm 19296-54623). Medially symmetric to slightly asymmetric. Laminae unlobed and toothed (serrate). Apex missing on all specimens, but likely acute; base acute and straight to slightly convex. Venation pinnate. Secondaries variable (not always well-preserved) from semicraspedodromous to eucamptodromous (e.g., see 00341-

58301), sometimes appearing brochidodromous; secondaries bend upward toward the apex about halfway between the midvein and the margin. Secondaries with excurrent to decurrent attachment to midvein and generally regular spacing and angle. Intersecondaries present; parallel to major secondaries until joining major secondary. Distal course of intersecondary perpendicular to subjacent major secondary. Intersecondary frequency usually one per intercostal area. Tertiaries generally percurrent. Higher order venation irregular, rarely preserved.

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One order of regularly spaced teeth present with 5 to 7 teeth per centimeter. Teeth appressed and small with angular sinuses and rounded apices. Teeth CV/CV to CV/ST to ST/CV in shape with rounded apices and longer proximal flanks than distal flanks. Tooth apex poorly preserved, but a bit of dark tissue present at the tip. Venation of tooth not preserved.

Discussion—These specimens have a thick pinnate primary and salicoid teeth. The venation is very irregular. The leaves have similarities both to Salix molesta MacGinitie from the Kisinger

Lakes sites in northwestern Wyoming (MacGinitie, 1974) and Pseudosalix handleyi Boucher,

Manchester, and Judd from the Green River Formation (Boucher et al., 2003).

Morphotype—OS: “Odd secondaries” (Figs. 2-58A & B).

Specimen—UF 19296-54645.

Description—Marginally attached lamina, microphyllous. Incomplete length 7.1 cm, width 2.2 cm. Slightly asymmetric in medial width; base not completely preserved. Lamina unlobed and toothed. Apex acute, not complete; base acute, likely straight. Venation pinnate; secondaries depart midvein at angles of 35 to 45° in center of leaf and travel towards the apex for a significant distance as they gradually approach the margin. Secondaries often branch when they are ~1/3 of the distance from the margin to the midvein. The two branches continue toward the apex in a nearly parallel course and appear to be eucamptodromous. Secondaries widely spaced with excurrent attachment to the midvein. Secondaries with a narrower angle between the midvein in the basal portion of leaf. Intersecondaries likely; details not preserved. Higher order venation appears irregular reticulate. One order of regularly to irregularly spaced teeth present.

Two to three teeth per centimeter; sinuses rounded. Teeth CC/CV in shape with pointed apices.

Principal vein present in tooth, entering in the apical half of the tooth and terminating at the apex.

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Discussion—Superficially, this specimen looks similar to morphotype HPT from the lower horizon, but the venation and tooth characters are quite different.

Morphotype—ST: “Saw teeth” (Figs. 2-59A & B).

Specimen—UF 19296-43808 (34).

Description—Marginally attached, petiolate laminae, notophyllous. Length >10 cm, width ~2.5 cm. Shape likely elliptic. Medially symmetric. Laminae unlobed and toothed. Neither base nor apex completely preserved, likely acute and straight. Venation pinnate. Secondaries semicraspedodromous. Possible marginal vein. Secondaries with slightly irregular spacing and a uniform angle to the midvein, diverging at ~40-50°. Secondaries with excurrent to occasionally decurrent attachment to the midvein. Intersecondaries present, parallel to major secondaries, length variable. Intersecondary distal course perpendicular to basiflexed to subjacent secondary.

Intersecondary frequency variable (0 to 2 per intercostal space). Tertiaries mixed percurrent, where visible. Exterior tertiaries looped and terminating at the margin. Higher order venation irregular reticulate where visible.

Two orders of teeth present with irregular spacing. Five to eight teeth per centimeter; sinuses rounded. Tooth shape ST/CV, to ST/ST to occasionally CV/CV with rounded apices.

Principle vein present, terminates at the apex or on the distal flank. Principle vein enters medially or slightly subapically. No glandular structures observed at tooth apices.

Discussion—This specimen has some features in common with the cf. Salix morphotype, but lacks salicoid glands on its teeth. It is possible they are not preserved, but that seems unlikely based on the number of teeth present. However, in other features (e.g., tooth shape, overall shape) morphotype ST looks similar to Salix cockerelli Brown from the Green River Formation

(MacGinitie, 1969).

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Morphotype—IT: “Irregular teeth” (Figs. 2-60A-C).

Specimen—UF 19296-54622.

Description—Lamina likely notophyllous. Lamina unlobed and toothed. Neither apex nor base preserved. Venation pinnate. Secondaries semicraspedodromous. Marginal secondary present.

Secondaries regularly spaced and angled, diverging from the midvein at ~60-75°. Secondaries with excurrent to decurrent attachment to the midvein. Intersecondaries present, specific characters not preserved. Higher order venation not preserved.

Two orders of irregularly spaced teeth. Four to five teeth per centimeter with generally rounded sinuses. Tooth shape variable from CC/CV to ST/CV to ST/ST. Principal vein present, entering subapically, terminating at the apex of the tooth. Dark “salicoid” like glands occasionally preserved at tooth apex.

Discussion—This specimen can be distinguished from 19296-43808 by its regularly spaced and angled secondaries. The secondaries diverge at a larger angle from the midvein than 19296-

43808. This specimen also has a prominent marginal vein and a clear “Y” shape formed by the secondaries about 1/3 of the way from the margin to the midvein. This pattern was not observed in 19296-43808. Finally, the secondaries bend more toward the apex and have more irregular spacing in specimen 19296-43808 as compared to this specimen, 19296-54622. This specimen also displays insect hole feeding with a strong reaction ring.

Morphotype—AV: “Actinodromous venation” (Figs. 2-61A7B).

Specimens—UF 19297-58109 (52, p), 58180 (24).

Description—Marginally attached, petiolate, microphyllous leaf. Length 4.2 cm, width 3.3 cm.

Shape ovate on one side, elliptic on the other. Medially and basally asymmetric in width. Lamina unlobed and toothed. Apex acute and ~straight; base obtuse and straight. Primary venation

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~basal actinodromous. Agrophics present. Major secondaries semicraspedodromous; minor secondaries semicraspedodromous. Major secondaries widely spaced with a similar angle and excurrent attachment. Intersecondaries not observed. Tertiaries mixed percurrent. Higher order venation not clearly preserved. Teeth regularly spaced; ~4 per centimeter. One order of teeth with slightly angular sinuses. Teeth are CV/CV in shape.

Discussion—The description is based on specimen 19297-58109 because 19297-58180 lacks an apex, base, intact margin, or venation above secondaries. This morphotype, AV, has similarities to Trochodendraceae.

Morphotype—PS: “Parallel secondaries” (Figs. 2-62A & B).

Specimen—UF 19297-43789 (27).

Description—Microphyllous, marginally attached fragment; complete lamina notophyllous.

Shape likely elliptic, but upper half of lamina missing. Base very asymmetrical in width. Lamina unlobed and toothed (serrate). Apex absent; base ~90° and straight on one side and convex on the other. Venation pinnate. Naked basal veins absent, however marginal secondary present.

Agrophics absent. Major secondaries appear semicraspedodromous, but they travel almost all the way to the margin and their final course is obscured. Major secondaries with very regular spacing (3-5 mm apart) and a uniform angle (~70°). Secondary attachment to the midvein excurrent to very slightly decurrent. Occasional intersecondaries, perpendicular to the midvein, less than 50% of subjacent secondary with a perpendicular distal course. Some intersecondaries bend toward the apex, whereas others bend toward the base. Tertiaries appear percurrent. Higher order venation appears irregular reticulate with possible freely ending veinlets, but is poorly preserved. Teeth widely spaced, base of lamina untoothed. One order of teeth with two teeth per centimeter where present. Sinuses appear slightly rounded. Tooth shape ST/CV to ST/ST.

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Discussion—The very evenly spaced and angled secondaries help to distinguish this morphotype from others at Blue Rim.

Morphotype—BN: “Broad notophyll” (Figs. 2-63A-C).

Specimen—UF 19297-43740 (64).

Description—Notophyllous leaf fragment. Shape likely elliptic. Lamina unlobed and toothed

(serrate). Apex and base missing—appear obtuse. Three primaries. Secondaries semicraspedodromous. Fimbrial vein present. Occasional intersecondaries, perpendicular to midvein, more than 50% subjacent secondary, distal course perpendicular to major secondary.

Tertiaries mixed percurrent. Higher order venation not preserved. Two to three regularly spaced teeth per centimeter. Sinuses rounded. Tooth shape CV/CV to CV/ST to ST/ST with a rounded apex. Principle vein present, terminates at the tooth apex.

Discussion—The likely broad shape of this specimen with multiple primaries and prominent rounded teeth help to distinguish it from others at Blue Rim.

Morphotype—ID: “Insect delight” (Figs. 2-64A & B).

Specimen—UF 19297-43681 (68).

Description—Notophyllous leaf fragment; base and apex missing. Medially symmetric; unlobed and toothed. Venation pinnate. Secondary course very close to the margin, secondaries semicraspedodromous. Secondaries slightly irregularly spaced, but have a uniform angle to the midvein with excurrent to decurrent attachment. Intersecondaries present, parallel to major secondaries, more than 50% the length of the subjacent secondary, with a distal course perpendicular to the subjacent major secondary with less than one per intercostal area. Tertiaries faint, but appear mixed percurrent with an obtuse angle to the midvein. Higher order venation not well preserved, likely irregular reticulate. Teeth widely spaced, ~2 per centimeter. Teeth have

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gently angled sinuses. Tooth shape poorly preserved, ranging from ST/ST to ST/CV to CC/CV with a slightly rounded tooth apex.

Discussion—This specimen can be recognized by its stout primary, semicraspedodromous secondaries, marginal vein, secondaries that travel nearly to the leaf margin, irregular reticulate higher order venation, and small teeth. Insect damage is present on this specimen. It looks like hole feeding and compares favorably to damage type DT07 (Labandeira et al., 2007).

Morphotype—AA: “Acute apex” (Figs. 2-65A & B).

Specimen—UF 19297-43667 (24).

Description—Marginally attached petiolate lamina, microphyllous. Length 4.5 cm by 1.4 cm wide for a length to width ratio of 3.2:1. Ovate leaf shape, generally symmetric. Lamina unlobed, toothed (serrate). Apex acute, straight. Base acute, straight. Venation pinnate. Secondaries semicraspedodromous. Possible fimbrial vein. Secondaries slightly irregularly spaced; angle smoothly decreasing proximately. Secondaries excurrent to slightly decurrent. Possible intersecondaries, but hard to distinguish from irregular tertiaries. Forth order venation irregular reticulate. Venation very loopy and irregular.

Teeth somewhat irregularly spaced with two orders. Five to six teeth per centimeter; sinuses angular. Tooth shape varies from ST/ST to CC/CV to ST/CV. Principle vein present terminating at the tooth apex or on the distal flank.

Discussion—This specimen has insect damage, likely surface feeding similar to DT29

(Labandeira et al., 2007). The insect damage, in addition to the pattern of the secondaries, helps to distinguish this specimen from the DE morphotype. In DE, the secondaries form well-defined loops. In contrast, in this specimen the secondaries almost form an intramarginal secondary,

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especially in the apex of the leaf. Overall, the venation is more irregular in this specimen than the

DE morphotype.

Morphotype—SP: “Stout primary” (Figs. 2-66A & B).

Specimen—UF 19297-58160 (76).

Description—Marginally attached lamina, microphyllous. Lamina bent, but shape appears elliptic. Symmetry cannot be determined with bent shape. Lamina unlobed and toothed (serrate).

Apex and base acute. Primary venation pinnate; primary stout. Secondaries brochidodromous to semicraspedodromous. Secondaries with a uniform angle to the midvein (close to 90°).

Secondaries with a generally excurrent attachment to the midvein. Numerous regularly spaced secondaries. Higher order venation not well preserved. Teeth ~irregular; one order. Sinuses rounded; tooth shape ST/ST to CC/CV. Principle vein present.

Discussion—The SP morphotype can be distinguished by its stout primary and numerous secondaries that are nearly perpendicular to the midvein.

Morphotype—PT: “Pointed teeth” (Figs. 2-67A-C).

Specimens—UF 19296-43822, 54657.

Description—Petiolate, marginally attached laminae, microphyllous to slightly larger in size.

Shape elliptic to oblong. Medially symmetric; base slightly asymmetric in width. Laminae unlobed and toothed. Apex not preserved; base acute and cuneate to slightly convex. Venation pinnate; one basal vein. Agrophics absent. Secondaries semicraspedodromous. No marginal vein observed. Secondaries generally uniformly spaced and angled. Secondaries with excurrent to decurrent attachment to the midvein. Intersecondaries present; parallel to major secondaries, more than 50% of length of subjacent secondary, distal course perpendicular to subjacent major secondary, frequency ~one per intercostal area. Tertiaries mixed percurrent. Exterior tertiaries

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looped. Quaternaries and quinternaries irregular reticulate. Areolation present with good development.

One order of regularly to slightly irregularly spaced teeth. Two teeth per centimeter; sinuses angular. Teeth ST/CV to CC/CV to CV/CV with pointed apices. Principle vein present, entering subapically. Principle vein terminates at the margin, ~at the apex of the tooth.

Accessory veins hug the margin on both the basal and apical side of each tooth.

Discussion—PT specimens look similar to morphotype TT from the lower horizon, but those specimens have basal insertion asymmetry, different intersecondary characters and ST/ST teeth.

These specimens are also similar to the upper horizon morphotype “Punctate laminar surface,” but these specimens lack surface glands and have more variation in their tooth shape.

Morphotype—PLS: “Punctate laminar surface” (Figs. 2-68A-E).

Specimens—UF 19296-43829 (7); UF 19297-43713 (208, ?, pp), 43762 (143, ?, f, pp); UF

19405-61641.

Description—Microphyllous, marginally attached laminae. Medially and basally asymmetric in width. Laminae unlobed and toothed. Apex and base likely acute; straight to slightly convex

(rarely preserved). Venation pinnate; secondaries craspedodromous to semicraspedodromous.

Secondaries regularly to slightly irregularly spaced, diverging from midvein at 60 to 70°.

Secondaries with excurrent attachment. Fimbrial vein present. Intersecondaries present, characters not preserved. Tertiaries likely percurrent; higher order venation not preserved.

One order of ~regularly spaced teeth. Two to four teeth per centimeter; sinuses angular to rounded. Tooth shape varies from ST/ST to CV/CV (subtly curved), to rarely CC/CV. Principle vein present with marginal termination. Tooth apex rounded with a dark pigmented gland at the tooth apex.

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Discussion—The laminar surface of these specimen is covered with glands (similar to the

“Aleurites” morphotype).

Untoothed Morphotypes

Morphotype—“YAB” (Figs. 2-69A-H).

Specimens—UF 00341-61868 (HOV pp), 61870 (?, f), 61872 (?, f); UF 19296-43827 (42, ?,

HOV pp, p, ss), 43832 (11, ?), 43834 (f, ?), 43835 (71, p), 43836 (30), 43837 (40, p), 43838 (46, p),43841 (55, ?, f, HOV wp), 43842 (32, HOV pp, p, ss), 43845 (52, ?), 43847 (67; 69, ?, HOV wp), 43848 (31, f), 43849 (27, ?), 43864 (f, ?), 54631 (?, f, HOV wp), 54632 (f, HOV wp),

54634 (?, pp), 54636 (?, f), 54637 (?, pp), 54638 (?, f), 54653 (?, f), 54655 (?), 54656 (?, f),

58245 (?, pp), 58249 (?, f); UF 19297-43666 (41, p, f), 43670 (25, ?), 43679 (80, ?, p), 43684

(65, 66), 43696 (163), 43707 (162, ?, p, pp), 43715 (177, HOV pp), 43722 (156, ?),43729 (197,

?), 43733 (73, p), 43755 (129, ?), 43757 (138, ?), 43759 (147, f), 43764 (150, p), 43776 (207, ?),

43778 (f), 43784 (184, patch of HOV), 43788 (55), 43792 (115), 43794 (112, p, wp), 43891 (15),

43900 (11, ?, f), 43901 (16), 43902 (f), 54205 (p), 54207 (p), 54209 (p, ?), 54211 (?, HOV pp, f),54214 (?, HOV pp), 54216 (HOV pp, ?), 54231 (f, ?), 54301 (p, ?), 54302 (p, HOV pp),54318

(f), 54341 (?), 54345 (f, HOV wp, ?), 54348 (?, HOV pp), 58097 (47, p, ?), 58098 (73, p, f),

58106 (55, ?), 58113 (69, f, ?), 58124 (72, HOV pp), 58125 (HOV pp, ?), 58158 (HOV pp, ?),

58187 (f, ?), 69732 (46 or 146); UF 19405-61631 (?, f), 61633, 61643 (?, f, p), 61652 (?, f),

61657 (?).

Description—Marginally attached, petiolate laminae microphyllous to mesophyllous. Preserved portion of the petiole is 1-2 mm wide (19296-43838; 19297-54205) and 1.8 cm long (19296-

43838). Length often incomplete, width ranges from approximately 2.5-3.0 cm. More complete specimens include: length 11.6 cm, width ~3.6 cm for an approximate length to width ratio of

3.2:1 (19297-43792). Length approximately 11.5 cm by 3.6 cm wide for a length to width ratio

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of 3.2:1 (19297-43755). Length 7.5 cm by 2.5 cm wide for a length to width ratio of 3:1 (19296-

43837) and length ~15.2 cm; width 4.5 cm for a ratio of 3.4:1 (19296-43838). Shape oblong to elliptic; medially symmetric. Base insertion asymmetrical or slightly asymmetric in width.

Laminae unlobed and untoothed. Apex acute and straight (occasionally trending toward a drip tip). Base acute and straight to convex in shape. Venation pinnate; no agrophics. Secondaries brochidodromous to rarely eucamptodromous; interior secondaries absent. Marginal secondary present. Secondaries regularly spaced and uniformly angled to angle smoothly increasing proximately. Secondaries usually with excurrent attachment, occasionally with decurrent attachment to midvein. Secondary angle to the midvein ranges from approximately 50 to 70° with slightly broader angles toward the base and narrower towards the apex. Intersecondaries present. Generally parallel to major secondaries, occasionally perpendicular. Generally no more than 50% of subjacent secondary, occasionally longer. Intersecondary distal course perpendicular to basifixed with subjacent major secondary. Frequency of intersecondaries approximately one per intercostal area. Tertiaries mixed percurrent to opposite percurrent to slightly irregular reticulate. Tertiaries with an obtuse angle to the midvein; exterior tertiaries looped. Quaternaries and quinternaries irregular reticulate, but rarely preserved. Areolation present, good development. Freely ending veinlets present, mostly with two or more branches, branching dichotomous.

Discussion—Many of the YAB specimens are poorly preserved (e.g., no apex or base, or no higher order venation) and do not have any unusual or identifying characters. It is possible that this morphotype includes more than one species, but based on the characters that were preserved they were lumped together. Leaves that had a similar overall shape (e.g., oblong to elliptic), sharply angled brochidodromous secondaries that dichotomized forming a “Y” pattern near the

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margin (essentially the secondaries bending to meet the adjacent secondary at an unusual angle), a marginal secondary, intersecondaries present, and secondaries with excurrent to decurrent attachment were included in this morphotype. Furthermore, many members of this group have the same type of marginal insect feeding—similar to DT12 (defined as: “circular, shallow to deep excision of leaf margin, <180 degrees of arc”) (Labandeira et al., 2007). A few specimens

(e.g., 19297-54214 & 19296-43864) have evidence of hole feeding. Some members of this morphotype (e.g., 19297-43755) have features in common with Cedrela schimperi (morphotype

TCE) identified from the lower horizon. Some of the specimens—especially the ones that look similar to TCE have a broader, more convex base and the secondaries in the basal portion of the leaf diverge at close to 90° (e.g., 19297-54214). There were some 19296 specimens that were not assigned to a morphotype, but may be representative of the YAB type. Most lacked the key characters to assign or the secondaries appeared to be eucamptodromous rather than brochidodromous (usually very faded near the margin).

Morphotype—“O” (Figs. 2-70A-E).

Specimens—UF 19296-54633 (?, f), 54651 (?); UF 19297-43702 (155), 43790, 58170 (67, ?).

Description—Laminae petiolate, marginally attached, and microphyllous to mesophyllous.

Length ~8 cm, width ~4 cm for a length to width ratio of 2:1 (19297-43790); length at least 14 cm, width ~6 cm for a length to width ratio of ~2.3:1 (19297-43702). Shape elliptic; medially symmetric. Laminae unlobed and untoothed. Apex acute and acuminate to slightly convex. Base acute and cuneate where visible. Venation pinnate. Secondaries brochidodromous; marginal secondary vein present, but not always preserved. Secondaries slightly irregularly spaced with slight variations in angle of attachment to the midvein. Secondaries with decurrent to excurrent attachment. Intersecondaries present, irregular, parallel to major secondaries varying to

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perpendicular to midvein. Intersecondaries more or less than 50% of subjacent secondary; distal course perpendicular to subjacent major secondary, occasionally contacting the secondary on the apical side, rather than the basal side. Occasionally more than one intersecondary per intercostal area. Tertiaries mixed percurrent to irregular reticulate. Quaternaries irregular reticulate; quinternaries irregular reticulate. Areolation present, good development. Freely ending veinlets present, mostly with two or more branches, branching appearing dichotomous.

Discussion—Although these specimens have some features in common with the large YAB morphotype, their intersecondaries have a different pattern. Furthermore, the secondaries form a slow arch toward the apex.

Morphotype—“Star” (Fig. 2-71A).

Specimen—UF 19297-43696 (164).

Description—Mesophyllous leaf fragment, likely elliptic, but full shape not perserved. Lamina untoothed and appears unlobed. Primary venation actinodromous, but base not preserved.

Agrophics present. Little margin preserved, so secondary type could not be determined. Fimbrial vein present; visible secondaries with excurrent attachment. Tertiaries opposite percurrent where visible, course variable including straight, convex, and forming a chevron pattern. Higher order venation irregular reticulate.

Discussion—This leaf is very broad compared to most of the other untoothed morphotypes from the upper horizon.

Morphotype—“Inverted triangle” (Figs. 2-72A-D).

Specimens—UF 19296-43839 (?); UF 19297-43721 (170, f).

Description—Marginally attached lamina, microphyllous; shape ovate to elliptic. Lamina likely symmetric; unlobed and untoothed. Apex missing. Base acute, straight to concave to slightly

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convex. Primary venation pinnate; secondaries brochidodromous. Marginal vein present (gauge borderline between secondaries and tertiaries). Secondaries with irregular spacing or decreasing proximally; angle seems to smoothly increase proximally (but apex missing). Secondaries with excurrent attachment. Possible intersecondaries, but challenging to separate from tertiaries.

Tertiaries not well preserved, but appear percurrent. Higher order venation not preserved.

Discussion—This morphotype can be distinguished from others in the upper horizon by its very acute straight base and opposite to subopposite secondaries with excurrent attachment.

Morphotype—“Loop” (Figs. 2-73A-D).

Specimens—UF 00341-61867; UF 19296-54648 (?); UF 19297-43685 (88), 43739 (79, f),

58171 (54, HOV pp).

Description—Marginally attached microphyllous to notophyllous laminae. Incomplete length 6.3 cm, width 1.65 cm for an approximate length to width ratio of 3.8:1 (19297-43685); length 6.9 cm, width 1.8 cm for a length to width ratio of 3.8:1 (19297-58171). Shape ovate to ~elliptic; medially and basally symmetric to asymmetric. Laminae unlobed and untoothed. Apex acute with a straight to acuminate shape; base acute to slightly obtuse and convex and straight in shape

(19297-58171). Venation pinnate; secondaries brochidodromous. Loops formed by the secondaries well aligned. Fimbrial vein present. Secondaries regularly spaced and angled, diverging from the midvein between 60 and 70°. Secondaries with excurrent attachment to the midvein. Intersecondaries present, perpendicular to the midvein, slightly more than 50% of subjacent secondaries, close to perpendicular to subjacent major secondary in distal course, sometimes more basiflexed, less than one per intercostal area. Tertiaries opposite to mixed percurrent where visible with a straight to slightly convex course. Angle of percurrent tertiaries obtuse. Higher order venation not preserved.

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Discussion—The “Loop” morphotype can be recognized by its generally skinny laminae, narrow acute, straight to barely convex base, brochidodromous secondary venation that forms large, wide loops, and opposite percurrent tertiaries. Specimen 19296-54648 was tentatively placed in this group because the venation characters match well, but it is much wider than the other specimens of the “Loop” morphotype.

Morphotype—“Marquise” (Figs. 2-74A-C).

Specimens—UF 19297-43661 (30, ?, ss), 43710 (178), 58164 (44, p).

Description—Marginally attached, petiolate, microphyllous laminae. Petiole ~0.7 mm wide by 3 mm long (19297-58164). Length 3.2 cm, width 1.4 cm for a length to width ratio of 2.3:1

(19297-58164). Shape elliptic to oblong. Medially symmetric; base symmetric to possibly having insertion asymmetry. Laminae unlobed and untoothed. Apex acute, convex with an emarginated tip. Base acute, straight. Primary venation pinnate. Secondaries faintly preserved, appear variable. Some brochidodromous, others meet prominent marginal secondary. Secondaries regularly spaced and angled with excurrent attachment to the midvein. Possible intersecondary, parallel to major secondary, more than 50% of subjacent secondary. Higher order venation not preserved.

Discussion—The description for the “Marquise” morphotype is mostly based on specimens

19297-43710 and 19297-58164. Specimen 19297-43661 is very small and may be representative of a juvenile leaf. It shares the same overall shape as 19297-43710 and has a marginal secondary in common with the other two specimens. However, the secondaries in 19297-43661 curve toward the apex once they leave the midvein, whereas the secondaries on 19297-43710 run in an almost a straight course once they leave the midvein. This morphotype can be partially recognized by its thick marginal vein and arching secondaries that travel to the margin.

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Morphotype—“Reverse teardrop” (Figs. 2-75A-F).

Specimens—UF 19297-43658 (34, p), 43669 (58, ?, p), 43706 (?, f), 43714 (187), 43720 (175, f), 43745 (71, p), 43777 (211, ?, f), 43786 (23, ?, p), 43800 (152, ?), 43899 (21?, 71?, f), 54215

(p, f, ?, pp), 54338 (pp), 58111 (71, ?, HOV pp).

Description—Marginally attached, petiolate laminae microphyllous to notophyllous. Estimated length 6.5 cm, width 2.2 cm for an estimated length to width ratio of 3.0:1 (19297-43714).

Laminar shape varies from ovate to elliptic. Laminae incomplete, but appear basally and medially symmetric. Leaves unlobed and untoothed. Apex not completely preserved on any specimen, but appears acute and straight. Base acute with a variable shape from slightly concave to straight or slightly convex. Primary venation basal to suprabasal actinodromous. Naked basal veins present (marginal secondary); 5 basal veins. Agrophics present; usually simple, rarely compound. Secondaries likely eucamptodromous, but travel towards the apex and a complete apex not preserved on any specimen. Marginal secondary present. Secondaries with excurrent to decurrent attachment. Tertiaries mixed percurrent, opposite more frequent. Tertiaries with an approximately perpendicular course to the midvein. Exterior tertiaries looped. Higher order venation not well preserved, but appears irregular reticulate.

Discussion—The “Reverse teardrop” specimens can be recognized by their multiple primaries that run in a parallel course toward the apex and the generally opposite, percurrent tertiaries. If all these specimens are truly one morphotype, the base shape is variable with specimens 19297-

43714 and 19297-43658 being concave, while specimens 19297-43745 and 19297-43669 are straight to slightly convex. Specimen 19297-43669 has an incomplete, but long petiole, preserved portion is 2.2 cm long. Specimen 19297-43720 has insect damage—hole feeding.

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Specimen 19297-43786 is very poorly preserved, but also has hole feeding and likely insect damage to the leaf margin.

Morphotype—“Eucamp” (Figs. 2-76A-C).

Specimens—UF 19297-43668 (59, p), 43678 (102, ?), 43686 (78).

Description—Marginally attached, petiolate laminae notophyllous; medially symmetric. Petiole thick, at least 1 cm long, laminar tissue extends along petiole (19297-43668). Laminae unlobed and untoothed. Base convex. Primary venation pinnate; secondaries eucamptodromous.

Secondaries regularly spaced and angled with excurrent attachment. Secondaries diverge at angles of 45-60° in the middle of the leaf with broader angles toward the base (~70°). Possible marginal secondary. Intersecondaries present, perpendicular to midvein. Higher order venation not preserved.

Discussion—None of the “Eucamp” specimens are particularly well preserved. This morphotype and the description encompassed all specimens with similar characters and eucamptodromous secondary venation. A few other specimens that were not able to be assigned to a morphotype may also belong to this taxon.

Morphotype—“Mesh” (Figs. 2-77A & B).

Specimen—UF 19297-43687 (86).

Description—Notophyllous lamina, unlobed and untoothed. No apex or base preserved; shape appears elliptic. Venation pinnate. Secondaries eucamptodromous transitioning to brochidodromous. Secondaries regularly spaced and angled with some secondaries excurrent and some strongly decurrent. Intersecondaries present, not parallel to major secondaries, but not perfectly perpendicular to midvein either. Intersecondary length ~50%, distal course perpendicular to subjacent major secondary, less than one per intercostal area. Tertiaries mixed

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percurrent with an obtuse angle to the midvein. Fourth order venation irregular reticulate; fifth order venation nearing regular reticulate. Areolation present, with good development. Freely ending veinlets not visible; venation makes a regular mesh.

Discussion—Although this specimen lacks an apex and base, it has well-preserved, well- organized higher order venation. It was compared with the YAB morphotype and has many features in common, but the lack of a marginal secondary vein and the almost regular reticulate quinternary venation warranted a separate morphotype.

Morphotype—SYZ: “Syzygioides” (Figs. 2-78A-H).

Species—Syzygioides sp.

Specimens—UF19296-43830 (?), 54646; UF 19297-43664, 43691 (99, ?), 43705 (204), 43723

(173), 43726 (168), 43747 (96, ?), 43749 (122, ?), 43760 (126), 43797 (120, 121), 43910 (2),

54226, 54326, 54335, 58116 (38), 58117 (?, p, pp), 58118 (58, ?), 58138 (64, ?, HOV pp), 58167

(57, ?), 58169; UF 19405-61647, 61649 (pp).

Description—Petiolate laminae nanophyllous to microphyllous with marginal attachment.

Length 3.8 cm, width 1.1 cm for a length to width ratio of 3.45:1 (19297-54326). Shape slightly ovate to linear to ~elliptic to ~oblong. Medially symmetric to slightly asymmetrical, base symmetrical to slightly asymmetrical (width and/or insertion). Laminae unlobed and untoothed.

Apex acute and straight to convex; base acute and straight to convex. Venation pinnate.

Secondaries brochidodromous meeting a prominent intramarginal secondary. Secondaries thin, closely and regularly spaced, with a uniform angle and excurrent to occasionally decurrent attachment to the midvein. Specimen 19297-58118 with one pair of acute basal secondaries.

Secondaries diverge at angles of ~40-50°. Intersecondaries present, usually one per intercostal

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area and parallel to the major secondaries. Higher order venation likely irregular reticulate. Other characteristics of the higher order venation could not be determined.

Discussion—The genus Syzygioides was established to include extinct myrtaceous taxa formerly placed in the genera Eucalyptus and Eugenia (Manchester et al., 1998). Syzygioides americana

(Lesquereux) Manchester, Dilcher, et Wing has been found at both Kisinger Lakes in northwestern Wyoming and in the Green River Formation (MacGinitie, 1969; MacGinitie, 1974;

Manchester et al., 1998). Syzygioides americana and specimens from the lower horizon are slightly different than these Blue Rim specimens from the upper horizon. The secondaries in S. americana do not loop, they just meet the intramarginal secondary, unlike these specimens.

However, this variation may be within the accepted framework of the species.

Morphotype—WSB: “Widely spaced (secondaries) balloon” (Figs. 2-79A-C).

Specimens—UF 00341-61869; UF 19296-43809 (29,?, f), 58227 (5); UF 19297-54319, 54696

(?), 58108 (60), 58173 (42, ?, HOV pp).

Description—Marginally attached laminae, notophyllous. Estimated length 9 cm (specimen missing an apex), width 4.1 cm (19297-54319). Shape ovate (may be close to elliptic, but apex missing). Medial symmetry likely symmetrical; base slightly asymmetrical in width. Laminae unlobed and untoothed. Apex appears acute (and straight), but not preserved on any specimen.

Base obtuse to acute and straight. Venation pinnate with one basal vein. Agrophics absent. Major secondaries brochidodromous to eucamptodromous. Secondaries with decurrent to excurrent attachment to midvein. Secondaries widely spaced near base (apex not preserved). Fimbrial vein present (tertiary gauge). Tertiaries opposite percurrent (rarely alternate percurrent). Epimedial tertiaries generally opposite percurrent, parallel to the intercostal tertiaries and perpendicular to the midvein. Higher order venation not preserved.

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Discussion—A leaf fragment (base only with a damaged margin and considerable insect damage, UF 19225-54579) from the lower horizon is likely the same morphotype as WSB.

However, the lower horizon specimen was not assigned to a morphotype because it was incomplete and could not be matched to any other specimens from the lower horizon. WSB is also similar to specimens (e.g., UF 19339-60188) recovered from the Wardell Ranch II (Douglas

Creek) site of the Green River Formation in Colorado. WSB also compares favorably to what

MacGinitie (1969) called Menispermites limacioides MacGinitie, also recovered from Wardell

Ranch. The venation of morphotype WSB is similar to some genera in Melastomataceae and

Lauraceae, but the taxonomic affinities remain unknown.

Morphotype—AL: “Aristolochia like” (Figs. 2-80A-E).

Specimen—UF 19297-58104 (40).

Description—Marginally attached lamina, mesophyllous. Length 9 cm, width 5.5 cm. Shape ovate. Medially and basally asymmetric in width. Lamina unlobed and untoothed. Apex acute and ~straight. Base obtuse, shape concavo-convex. Primary venation pinnate. Base near petiole attachment not completely preserved, but it looks like 5 basal veins present. Compound agrophics present. Major secondaries simple brochidodromous. Interior secondaries absent; minor secondaries brochidodromous. Fimbrial vein present. Major secondaries gradually increasing proximally in spacing; angle smoothly decreasing proximally. Secondaries with excurrent attachment to the midvein. Intersecondaries absent. Tertiaries mixed percurrent with a generally obtuse angle to the midvein. Epimedial tertiaries mixed percurrent and generally perpendicular to the midvein. Exterior tertiaries looped. Quaternaries irregular reticulate.

Quinternaries almost regular reticulate. Areolation present, good development. Possible freely ending veinlets present or reticulate 6th order venation, unclear.

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Discussion—This specimen is similar to Aristolochia solitaria MacGinitie, a species documented from Kisinger Lakes in northwestern Wyoming (MacGinitie, 1974). The most notable difference is that the Kisinger Lakes specimens have a cordate base, whereas the Blue

Rim specimen is concavo-convex. In other features (e.g., overall shape, apex, venation) the

Kisinger Lakes specimens and this specimen are very similar. Aristolochia solitaria is also listed as a rare element of the flora at Kisinger Lakes (MacGinitie, 1974); this morphotype is only represented by one specimen at Blue Rim. A different species of Aristolochia, A. mortua

Cockerell is present in the Green River flora, but that species seems to be broader with more extensive agrophics than the Kisinger Lakes or Blue Rim material.

Morphotype—X (Fig. 2-81A).

Specimen—UF 19297-54297.

Description—Marginally attached lamina, microphyllous. Incomplete length 5.5 cm, width 1.5 cm. Shape elliptic. Unlobed, untoothed leaf. Apex and base acute, but incomplete. Primary venation pinnate. Secondaries brochidodromous where visible. Secondaries widely spaced with variable attachment to the midvein, decurrent to excurrent. Secondaries diverge at 40-45° from midvein in center of lamina. Intersecondaries not obvious. Higher order venation irregular reticulate.

Discussion—Secondaries are widely spaced for the size of the lamina (6-10 mm apart in the center of the leaf).

Morphotype—Legume (Figs. 2-82A-F).

Specimens—UF 19296-43843, 43846 (63), 54643, 58254 (2).

Description—Marginally attached petiolate laminae, microphyllous to notophyllous. Petiole short, ~3.5 mm long and ~1.5 mm wide (19296-58254). Medially symmetric; slightly

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asymmetrical in basal width. Laminae unlobed and untoothed. Apex not preserved; base obtuse and convex. Venation pinnate, midvein vertically striated. One basal vein. Agrophics absent.

Secondaries brochidodromous. Marginal secondary present. Secondaries with regular spacing and angle to the midvein. Secondaries with excurrent to decurrent attachment to the midvein.

Higher order venation not well preserved on any specimen.

Discussion—The short petiole with a pulvinus indicates these specimens are representative of

Fabaceae. All four specimens assigned to this morphotype have a very uniform base shape.

Wood assigned to Fabaceae (traditional subfamily Caesalpinioideae) has been recovered from

Blue Rim. Legume leaflets have also been recovered from the Kisinger Lakes site in northwestern Wyoming (MacGinitie, 1974) and the Green River Formation (MacGinitie, 1969).

However, as none of the Blue Rim specimens have an apex or higher order venation, it is difficult to compare in detail to these other species.

Morphotype—CV: “Curved venation” (Fig. 2-83A).

Specimen—UF 19296-54652.

Description—Marginally attached, microphyllous lamina. Laminar shape likely elliptic; symmetry not preserved. Lamina unlobed and untoothed. Apex and base not preserved, but apex likely acute and straight. Venation pinnate; secondaries brochidodromous. Marginal secondary present. Secondaries with slightly irregular spacing, angle slightly inconsistent ~35° in basal part of leaf, 35° to 50° mid lamina. Secondaries with excurrent attachment to midvein.

Intersecondaries present, usually parallel to major secondaries, occasionally closer to perpendicular. Intersecondaries <50% or ~50% of length of subjacent secondary. Intersecondary distal course perpendicular to subjacent secondary. Intersecondary frequency 0-2 per intercostal space, one most common. Tertiaries mixed percurrent. Tertiaries with an obtuse angle to the

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midvein. Epimedial tertiaries generally opposite percurrent. Exterior tertiaries looped.

Quaternaries and quinternaries regular to irregular reticulate. Areolation present with good development.

Discussion—This specimen has more irregularly spaced and curved secondaries than “YAB.”

The angles of the secondaries in the basal part of the leaf are too sharp to match with morphotype

“O.” Morphotype “Mesh” does not have a marginal secondary like this specimen. This specimen looks similar to specimen 19404-61699 (Fig. 2-16B) from the isolated channel fill.

Monocot Foliage

Specimens—UF 19296-58258, 58241; UF 19297-54324, 58155, 58176, 58186; UF 19405-

61645.

Discussion—Occasional strap like leaves with parallel venation indicate the presence of monocots in the upper horizon. These leaves lack midveins and range from ~6 to 16 mm wide.

The major veins are 0.7-1.7 mm apart. At least three types of monocot leaves are present.

Specimen 19296-58241 has perpendicular cross veins that follow an irregular course. Other specimens (e.g., 19297-58186) have thinner gauge parallel veins in-between the larger veins.

These are evenly spaced and less than 1/10 mm apart. A third type (19297-54324), with the widest leaves (~1.6 cm), has major veins that are just over 1 mm apart and cross veins that follow a straight, but diagonal course in relation to the main vertical veins. These may be representative of Poales.

Non-Angiosperm Remains

Genus—Equisetum sp.

Specimens—UF 19296-58233; UF 19297-43695, 43751.

Discussion—Horsetails are represented by fragments of the characteristic jointed stems.

Species—Lygodium kaulfussi Heer.

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Specimens—UF 19296-54626, 54627; UF 19297-43705, 43721, 58110; UF 19405-61632,

61651.

Discussion—Lygodium is present in the upper horizon, but not as overwhelmingly abundant as found in the lower horizon.

Species—cf. Asplenium sp.

Specimens—UF 19296-43801, 43806, 43807, 43824, 54659, 58242, 58260; UF 19297-43704,

54212, 58099, 58144; UF 19405-61656.

Species—cf. Acrostichum sp.

Specimens—UF 19297-54220, 58152 (?).

Species—cf. Thelypteris iddingsi (Knowlton) MacGinitie

Specimens—UF 19297-43774, 43793, 54236

Species—cf. Allantodiopsis sp.

Specimen—UF 19405-61640.

Summary of Upper Horizon Leaves

The upper horizon includes the quarries of UF 00341, 19296, 19297, and 19405. Thirty six leaf morphotypes are present including 21 toothed and 15 untoothed. Thirteen morphotypes are represented by single specimens (8 toothed and 5 untoothed). This is the most species rich leaf assemblage of the three horizons studied at Blue Rim. It remains uncertain whether these differences in diversity and taxonomic composition between the three horizons are due to floristic change including the arrival of some new elements to the flora, or may be due more to taphonomic or sampling biases associated with somewhat different depositional environments.

Taxa including Macginitiea wyomingensis and Cedrelospermum nervosum are shared with the isolated channel fill quarry (UF 19404), whereas Populus cinnamomoides and Serjania rara are present at all three horizons (Table 2-1). The flora is dominated by dicotyledonous

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angiosperms with a few ferns; conifers appear to be absent. Although the taxonomic identity of many of the upper level leaves remains uncertain, there is good evidence for recognition of

Ulmaceae, Salicaceae, Platanaceae (2 spp.), Anacardiaceae and Fabaceae. The associated reproductive structures from the upper horizon (treated separately in Chapter 3) include some winged fruits (e.g., Chaneya tenuis, Illigera eocenia) which provide additional clues to the vegetation of this interval.

Overall Discussion of Blue Rim Leaves

The leaf flora at Blue Rim is represented by at least 69 morphotypes. Twelve morphotypes are present in more than one horizon. Both the UF 19404 quarry and the upper horizon are more species rich than the lower horizon, which was more intensively sampled. It is possible that a few of the leaves not assigned to a morphotype from the lower horizon represent additional species, but there would still be fewer morphotypes than the other two horizons. Only two taxa are present in all three horizons: Populus cinnamomoides and Serjania rara. The UF

19404 site shares the highest percentage (35.7%) of its leaves with the other horizons, whereas the lower and upper horizons each have ~30% of their morphotypes in common with the other horizons.

Comparison of leaves from the UF 19404 locality and the lower horizon. Although the UF 19404 quarry has significantly fewer leaves (~200) than the combined quarries of the lower horizon (~600 numbered and morphotyped leaves), it is more diverse with 28 morphotypes. The lower horizon only has 20 morphotypes. However, in general, specimens from the lower horizon are better preserved with more higher order venation visible. Populus cinnamomoides, Serjania rara, and “Aleurites” fremontensis are present in both the lower horizon and the UF 19404 isolated channel fill (Table 2-1).

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Comparison of leaves from the UF 19404 locality and the upper horizon. These two units have more in common with each other (9 shared taxa) than either does to the lower horizon

(Table 2-1). They both seem to have more floral elements in common with the Green River

Formation (e.g., Macginitiea wyomingensis, Cedrelospermum nervosum) than the lower horizon.

By contrast, the lower horizon has more taxa in common with the Kisinger Lakes site in northwestern Wyoming.

Comparison of leaves from the lower horizon and upper horizon. Even though some taxa are shared between the upper and lower horizon, they do not always occur in the same abundance. For example, specimens of Serjania rara are common in the lower horizon, but rare in the upper horizon. Other morphotypes that may be shared (e.g., lower GBT with upper AV and lower HPT with upper MLA) are poorly preserved or only represented by a few specimens making a full comparison challenging.

Non-Angiosperms. No gymnosperm foliage was recovered from any horizon at Blue

Rim. However, ferns were present. Lygodium kaulfussi, represented by both fertile and sterile foliage, was most abundant in the lower horizon. However it was also observed in the upper horizon and the UF 19404 channel fill quarry. Other fern taxa assignable to Polypodiales, including Acrostichum sp., Asplenium sp., and Thelypteris iddingsi, were more common in the upper horizon.

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Table 2-1. Morphotypes present in more than one leaf horizon are listed in the same row. Morphotypes in parenthesis are tentatively matched; often specimens from one of the horizons were poorly preserved. Morphotypes not listed here are not shared with either of the other two leaf horizons at Blue Rim. The UF 19404 quarry shares 10 of its 28 morphotypes with the other horizons, mostly with the upper level. The lower horizon has the highest percentage of unique taxa (70%) and the upper horizon shares 11 of its 36 morphotypes with other horizons at Blue Rim. UF 19404 Lower Horizon Upper Horizon Toothed 1: Macginitiea MAC: Macginitiea wyomingensis wyomingensis Toothed 4 DE Toothed 6: cf. Populus PC: Populus PC-U: Populus cinnamomoides cinnamomoides cinnamomoides Toothed 7: cf. Cedrelospermum CN: Cedrelospermum nervosum nervosum Toothed 12: Serjania rara SR: Serjania rara SR-U: Serjania rara AF: "Aleurites" Toothed 13: "Aleurites" fremontensis fremontensis (TCE: "Cedrela" (Entire 1) schimperi) (YAB) Entire 7 Reverse teardrop Entire 10 Aristolochia Entire 14 WSB (GBT) (AV) (HPT) (MLA)

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Figure 2-1. Morphotype Toothed 1; Macginitiea wyomingensis (Knowlton and Cockerell) Manchester. A) UF 19404-61694’. B) UF 19404-61718. C) UF 19404-61696. D) UF 19404-61691’. E) UF 19404-61706. F) Close-up view of UF 19404-61706.

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Figure 2-2. Morphotype Toothed 2. A) UF 19404-61691. B) UF 19404-61691’.

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Figure 2-3. Morphotype Toothed 3. A) UF 19404-61723. B) UF 19404-61723’.

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Figure 2-4. Morphotype Toothed 4. A) UF 19404-61686. B) UF 19404-61686’. C) UF 19404- 61671.

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Figure 2-5. Morphotype Toothed 5. A) UF 19404-61716. B) UF 19404-61716’. C) UF 19404- 61715.

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Figure 2-6. Morphotype Toothed 6; cf. Populus cinnamomoides (Lesquereux) MacGinitie. A) UF 19404-61693. B) Close-up of UF 19404-61693. C) UF 19404-61693’.

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Figure 2-7. Morphotype Toothed 7. A) UF 19404- 61663. B) UF 19404-61663’.

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Figure 2-8. Morphotype Toothed 8. A) UF 19404-61675.

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Figure 2-9. Morphotype Toothed 9. A) UF 19404-61660. B) UF 19404-61660’.

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Figure 2-10. Morphotype Toothed 10. A) UF 19404-61702.

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Figure 2-11. Morphotype Toothed 11. A) UF 19404-61717.

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Figure 2-12. Morphotype Toothed 12; Serjania rara MacGinitie. A) UF 19404-61709.

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Figure 2-13. Morphotype Toothed 13; “Aleurites” fremontensis (Berry) MacGinitie. A) UF 19404-61685. B) UF 19404-69291. C) UF 19404-61676’.

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Figure 2-14. Morphotype Toothed 14. A) UF 19404-61676. B) UF 19404-61676’.

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Figure 2-15. Morphotype Entire 1. A) UF 19404-61688. B) UF 19404-61662. C) UF 19404- 61712. D) UF 19404-61692’. E) UF 19404-61667. F) UF 19404-61668. Digital scale bars = 10 mm.

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Figure 2-16. Morphotype Entire 2. A) UF 19404-61674. B) UF 19404-61699. C) UF 19404- 61689. D) UF 19404-61708. E) UF 19404-61700. F) UF 19404-61690.

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Figure 2-17. Morphotype Entire 3. A) UF 19404-61687. B) UF 19404-61687’.

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Figure 2-18. Morphotype Entire 4. A) UF 19404-61713. B) UF 19404-61713’.

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Figure 2-19. Morphotype Entire 5. A) UF 19404-61707. B) UF 19404-61684. C) UF 19404- 61664.

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Figure 2-20. Morphotype Entire 6. A) UF 19404-61661.

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Figure 2-21. Morphotype Entire 7. A) UF 19404-61721’. B) UF 19404-61721. C) UF 19404- 61665.

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Figure 2-22. Morphotype Entire 8. A) UF 19404-61701. B) UF 19404-61701’. C) UF 19404- 61704. D) UF 19404-61712. E) UF 19404-61712’.

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Figure 2-23. Morphotype Entire 9. A) Close-up of apex of UF 19404-61670’. B) UF 19404- 61670’. C) UF 19404-61670.

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Figure 2-24. Morphotype Entire 10. A) UF 19404-61719’.

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Figure 2-25. Morphotype Entire 11. A) UF 19404-61708. B) UF 19404-61710.

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Figure 2-26. Morphotype Entire 12. A) UF 19404-61683. B) UF 19404-61683’.

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Figure 2-27. Morphotype Entire 13. A) UF 19404-61672’. B) Close-up of UF 19404-61672’. C) UF 19404-61672. D) UF 19404-61703.

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Figure 2-28. Morphotype Entire 14. A) UF 19404-68888.

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Figure 2-29. Morphotype HT, a new species in the tribe Homalieae (Salicaceae). A) UF 15761N- 61455. B) UF 15761N-61379. C) UF 19225-51976. D) UF 15761N-43974. E) UF 15761N-61381’. F) Close-up of tertiaries, UF 15761N-61381. G) Close-up of teeth, UF 15761N-61452’. Scale bars A-E = 10 mm; scale bars F & G = 5 mm.

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Figure 2-30. Morphotype VCT. A) UF 15761N-61459’. B) UF 15761N-61415. C) UF 15761N- 43951. D) UF 15761N-43940’. E) UF 15761N-61375’. F) UF 15761N-61402. Digital scale bars = 10 mm.

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Figure 2-31. Morphotype SR, Serjania rara MacGinitie. A) UF 15761N-43934. B) UF 19225- 54606. C) UF 15761S-57786. D) UF 19225-57093. E) UF 15761N-61430. F) UF 15761N-61424 with terminal and lateral leaflet. G) Specimen UF 19225-54607 with multiple leaflets preserved. H) UF 15761N-61434. I) UF 19031-39021. J) UF 19032- 39004.

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Figure 2-32. Morphotype AF, “Aleurites” fremontensis (Berry) MacGinitie. A) UF 15761- 55203. B) UF 18289-56301. C) UF 15761N-57452’. D) UF 15761N-57451. E) UF 18288-56285. F) UF 18289-56300. G) UF 18289-56286. H) UF 18289-56350. Digital scale bars = 10 mm.

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Figure 2-33. Morphotype PC, Populus cinnamomoides (Lesquereux) MacGinitie. A) UF 19225- 51961. B) UF 19031-39015. C) UF 19225-51959. D) Close-up of UF 19225-51962. E) UF 19225-51964. F) UF 19225-57055. G) UF 19225-51962. H) UF 15761N- 43982. I) UF 19225-51960 with long petiole preserved. Digital scale bars = 10 mm.

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Figure 2-34. Morphotype GBT. A) UF 19337-61592. B) UF 19337-57985. C) UF 19337-58064. D) UF 15761N-61468. E) UF 15761N-61471.

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Figure 2-35. Morphotype TDA/PS. A) UF 15761N-57652. B) UF 15761S-57877. C) UF 15761N-57410. D) UF 15761S-57883.

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Figure 2-36. Morphotype CBT. A) UF 15761S-57828. B) UF 19225-54614. C) UF 15761S- 57829. D) UF 19225-51978. E) UF 19225-56997’. F) UF 19225-56998.

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Figure 2-37. Morphotype RL. A) UF 15761-55216. B) UF 15761N-61378. C) UF 15761-55217’. D) UF 15761-55222. E) UF 15761-55221. F) UF 15761-55234. G) UF 15761-55208.

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Figure 2-38. Morphotype TT. A) UF 19337-61584’. B) UF 19337-61584. C) UF 19337-61591.

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Figure 2-39. Morphotype ATR. A) UF 19225-54602’. B) UF 19225-54602. C) UF 15761-49826.

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Figure 2-40. Morphotype HPT. A & B) UF 15761-55235 (2 lamina on same hand sample).

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Figure 2-41. Morphotype TCE, Cedrela schimperi (Lesquereux) MacGinitie. A) UF 19225- 56991. B) UF 19337-58044. C) UF 19225-57034’. D) UF 19225-57110. E) UF 19225-56939. F) UF 19225-56966.

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Figure 2-42. Morphotype TRB. A) UF 15761-55186. B) UF 15761S-57840. C) UF 15761- 55187.

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Figure 2-43. Morphotype BTBP. A) UF 15761N-43995. B) UF 15761N-61383’. C) UF 15761N- 61495. D) UF 15761N-57665. E) UF 15761N-61465. Digital scale bars = 10 mm.

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Figure 2-44. Morphotype BTY. A) UF 15761-55200. B) UF 15761N-57657. C) The largest leaf recovered from Blue Rim, UF 15761N-43996. D) UF 15761N-61417.

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Figure 2-45. Morphotype BTOS. A) UF 15761N-61420. B) Close-up view showing irregular venation, UF 15761N-61420. C) UF 15761N-61420’. Digital scale bars = 10 mm.

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Figure 2-46. Morphotype SYZ, Syzygioides americana (Lesquereux) Manchester, Dilcher et Wing. A) UF 19337-58080. B) UF 18289-56297. C) Close-up of UF 18289-56297. D) UF 15761-55245’. E) UF 15761-55248. F) UF 15761-55250’. G) UF 15761- 55251.

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Figure 2-47. Morphotype SYM, Symplocos incondita MacGinitie. A) UF 19032-39008. B) Close-up of UF 19032-39008. C) Close-up of UF 19032-39014. D) UF 19032-39014.

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Figure 2-48. Specimens assigned to Morphotype “DE.” A) UF 19297-43716. B) UF 19297- 58129. C) UF 19405-61657. D) UF 19297-54223. E) UF 19297-54317. F) UF 19297- 43693’. G) UF 19297-43912. H) UF 19297-54321. I) UF 19297-58102. J) UF 19297- 54697. Scale bars = 10 mm.

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Figure 2-49. Specimens assigned to “MAC,” Macginitiea wyomingensis (Knowlton and Cockerell) Manchester. A) UF 19297-43757’ B) UF 19297-54208. C) UF 19297- 43737. D) UF 19296-54624. Scale bars = 10 mm.

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Figure 2-50. Specimens assigned to morphotype “PL,” Platanus sp. A) UF 19297-58126. B) UF 19297-43910’. C) UF 19297-43676. D) UF 19297-43728. Scale bars = 10 mm.

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Figure 2-51. Specimen assigned to “CN,” Cedrelospermum nervosum (Newberry) Manchester. A) UF 19297-54222. B) UF 19297-54222’. C) UF 19297-43781. D) UF 19297- 54235.

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Figure 2-52. Specimens assigned to “RN,” Rhus nigricans (Lesquereux) Knowlton. A) UF 19297-54234. B) UF 19297-58136. C) UF 19297-43796. D) UF 19297-43742’. E) UF 19297-43738’. F) UF 19297-43725. G) UF 19296-54625. Scale bars = 10 mm.

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Figure 2-53. Specimens assigned to “AT,” “Aleurites” sp. A) UF 19297-54230. B) UF 19297- 54230’. C) UF 19297-58141. Scale bars = 10 mm.

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Figure 2-54. Specimens assigned to “SR-U,” Serjania rara MacGinitie. A) UF 19297-43763. B) UF 19297-43890’. C) UF 19297-43904. Scale bars = 10 mm.

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Figure 2-55. Specimens assigned to “MLA: Mac look alike.” A) UF 19297-43732. B) UF 19297- 43732’. C) Close-up of UF 19297-43732. D) UF 19297-54345. Scale bars = 10 mm.

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Figure 2-56. Specimens assigned to “PC-U,” Populus cinnamomoides (Lesquereux) MacGinitie. A) UF 19297-43768. B) UF 19297-43718. C) UF 19297-58105’. Scale bars = 10 mm.

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Figure 2-57. Specimens assigned to “CS.” cf. Salix sp. / cf. Pseudosalix sp. A) UF 19297-43674. B) UF 19297-43895’. C) UF 19297-43758. D) UF 00341-58301. E) UF 19297- 43772. F) UF 19296-54623. Scale bars = 10 mm.

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Figure 2-58. Morphotype “OS: Odd secondaries.” A) UF 19296-54645. B) Close-up UF 19296- 54645. Scale bars = 10 mm.

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Figure 2-59. Morphotype “ST: Saw teeth.” A) UF 19296-43808. B) UF 19296-43808’.

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Figure 2-60. Morphotype “IT: Irregular teeth.” A) UF 19296-54622. B) UF 19296-54622’. C) Close-up of UF 19296-54622. Scale bars = 10 mm.

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Figure 2-61. Morphotype “AV: Actinodromous venation.” A) UF 19297-58109. B) UF 19297- 58180.

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Figure 2-62. Morphotype “PS: Parallel secondaries.” A) UF 19297-43789. B) UF 19297-43789’.

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Figure 2-63. Morphotype “BN: Broad notophyll.” A) UF 19297-43740. B) Close-up of UF 19297-43740. C) UF 19297-43740’.

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Figure 2-64. Morphotype “ID: Insect delight.” A) UF 19297-43681. B) UF 19297-43681’.

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Figure 2-65. Morphotype “AA: Acute apex.” A) UF 19297-43667. B) UF 19297-43667’.

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Figure 2-66. Morphotype “SP: Stout primary.” A) UF 19297-58160. B) UF 19297-58160’.

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Figure 2-67. Morphotype “PT: Pointed teeth.” A) UF 19296-43822. B) UF 19296-43822’. C) UF 19296-54657. Scale bars = 10 mm.

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Figure 2-68. Morphotype “PLS: Punctate laminar surface.” A) UF 19296-43829. B) UF 19296- 43829’. C) UF 19405-61641’. D) UF 19297-43762. E) UF 19297-43713’. Scale bars = 10 mm.

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Figure 2-69. Specimens assigned to morphotype “YAB.” A) UF 19297-43792. B) UF 19297- 54205. C) UF 19297-43794’. D) UF 19296-43838’. E) UF 00341-61868. F) UF 19296-43837. G) UF 19296-43836. H) Close-up of UF 19297-54302. Scale bars = 10 mm.

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Figure 2-70. Specimens assigned to morphotype “O.” A) UF 19297-43702. B) UF 19297-43790. C) UF 19297-58170. D) UF 19296-54651. E) UF 19296-54633’. Scale bars = 10 mm.

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Figure 2-71. Morphotype “Star.” A) UF 19297-43696. Scale bar = 10 mm.

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Figure 2-72. Morphotype “Inverted triangle.” A) UF 19297-43721. B) UF 19297-43721’. C) UF 19296-43839. D) UF 19296-43839’.

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Figure 2-73. Specimens assigned to morphotype “Loop.” A) UF 19297-43685. B) UF 19297- 58171. C) UF 19297-43739. D) UF 19296-54648. Scale bars = 10 mm.

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Figure 2-74. Specimens assigned to morphotype “Marquise.” A) UF 19297-58164. B) UF 19297-43710. C) UF 19297-43661. Scale bars = 10 mm.

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Figure 2-75. Specimens assigned to morphotype “Reverse teardrop.” A) UF 19297-43714’. B) UF 19297-43658’. C) UF 19297-43720. D) UF 19297-54338. E) UF 19297-43745. F) Close-up of UF 19297-43745’. Scale bars = 10 mm.

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Figure 2-76. Specimens of morphotype “Eucamp.” A) UF 19297-43668. B) UF 19297-43686. C) UF 19297-43678’. Scale bars = 10 mm.

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Figure 2-77. Morphotype “Mesh.” A) UF 19297-43687. B) UF 19297-43687’. Scale bar = 10 mm.

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Figure 2-78. Morphotype SYZ, Syzygioides sp. A) UF 19405-61649. B) UF 19297-43705’.C) UF 19297-54326. D) UF 19405-61647. E) UF 19297-43726’. F) UF 19297-43723. G) UF 19297-43760. H) UF 19297-54226. Scale bars = 10 mm.

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Figure 2-79. Specimens assigned to morphotype “WSB: Widely spaced (secondaries) balloon.” A) UF 19297-54319. B) UF 00314-61869. C) UF 19297-58108. Scale bars = 10 mm.

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Figure 2-80. Specimens assigned to “AL: Aristolochia like.” A) UF 19297-58105. B) UF 19297- 58104’. C) Close-up of UF 19297-58104’. D) Close-up of UF 19297-58104. E) Close-up of UF 19297-58104. Scale bars = 10 mm.

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Figure 2-81. Morphotype “X.” A) UF 19297-54297. Scale bar = 10 mm.

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Figure 2-82. Specimens assigned to the legume morphotype. A) UF 19296-58254. B) UF 19296- 58254’. C) UF 19296-43846. D) UF 19296-43846’. E) UF 19296-54643. F) UF 19296-43843.

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Figure 2-83. Morphotype “CV: Curved venation.” A) UF 19296-54652. Scale bar = 10 mm.

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CHAPTER 3 REPRODUCTIVE STRUCTURES: MACROFOSSILS AND DISPERSED PALYNOFLORA

Although the fossil leaves documented in the previous chapter are more abundant in the

Bridger flora, the associated reproductive structures provide important new clues as to the systematic affinities of the plants growing in this region approximately 49 Ma. At least seven types of flowering structures are recognized from well-collected exposures along the Blue Rim escarpment (UF localities 15761/15761N/15761S, 19225, 19225N, 19296, 19337, 19338) in

Sweetwater County, Wyoming. Only one of these, Landeenia aralioides, was published prior to my work on the Blue Rim flora (Manchester and Hermsen, 2000). Fruits and seeds of Landeenia aralioides (an extinct genus of likely sapindalean affinity) are also preserved.

The remaining floral structures are documented here in Part I and include: 1) Phoenix windmillis S.E. Allen, sp. nov. 2) “Mini Spike,” a spicate inflorescence with flowers or fruits preserved in multiple orientations (possibly spiral) that range from 1 to 1.5 mm in width. 3)

“Sunburst,” a flower of Salicaceae with eight tepals, each having a prominent elliptical gland at the base, and numerous stamens (~50-100) containing reticulate, tricolpate pollen. 4) “Poofball,” a globose to ellipsoidal inflorescence that varies from ~1.7 to 4.2 cm in diameter often with protruding stamens containing monoporate pollen. 5) Tiny five-tepaled flowers with prominent stamens having relatively long filaments and large anthers. 6) Cup-like flowers with tiny stamens. 7) Flowers with a pronounced central vein on each unit of the perianth, possibly with affinities to Pseudosalix and 8) Large stamens. Although many of these flowers and inflorescences have distinct characters, their taxonomic affinity has not been resolved. Often diagnostic features are missing or the characters do not match any extant clades, suggesting they represent extinct taxa.

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Part II documents multiple species that are represented by fruits and occasional seeds.

Fruits of Macginicarpa, cf. Ampelopsis (and seeds), cf. Pseudosalix, Populus, Chaneya tenuis,

Pentoperculum minimus, Iodes brownii, Iodes occidentalis, Illigera eocenia, and Lagokarpos lacustris are present along with seeds of Keratospermum. A few fruits and seeds of unknown taxonomic affinity are also preserved at Blue Rim. These are documented as either occurring as single units or in clusters/aggregates. In sum, there are at least 30 unique reproductive macrofossils at Blue Rim (Table 3-1). Although some of these reproductive structures are aligned with co-occurring leaves at Blue Rim (e.g., Populus, Macginicarpa, Iodes occidentalis), many others are not and therefore increase the overall diversity from this latest Early Eocene site.

Part III provides a brief overview of the dispersed palynoflora at Blue Rim. Pollen and spores are preserved at more stratigraphic levels than the macrofossils and are likely representative of both the regional and local flora. For example, conifer taxa including Pinus are relatively common in the dispersed palynoflora, but only one macrofossil specimen (wood) representative of Pinaceae has been recovered.

Part I: Flowers and Inflorescences

Species—Phoenix windmillis S.E. Allen, sp. nov.

Phoenix windmillis flowers have three petals, six stamens, and range from 6.6 to 9 mm in diameter. In situ pollen from specimens of P. windmillis from the Barrel Springs locality of the

Green River Formation provided additional characters to assist in identifying these specimens as data palms. This floral morphotype is documented in detail in Chapter 4 and was previously published (Allen, 2015a).

Morphotype—“Mini Spike” (Figs. 3-1A-F; 3-21D).

Species—cf. Clethra? lepidioides Cockerell 1925; cf. Antholithes pendula Brown 1929.

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Specimens—UF 15761-22588, 22589, 22590; UF 15761N-43973, 43998, 57427, 57428, 57429,

57430, 57431, 57432, 57433, 57434, 57435, 57436, 57437, 57438, 57439, 57440, 57441, 57442,

57443, 57444, 57448, 57463, 61386, 61433, 61441 (?), 61449, 61451 (?).

Description—Inflorescences elongated, likely indeterminate, with small, sessile flowers. Spikes range in size; with the larger examples being greater than 3.5 cm in length (individual inflorescences usually broken at one or both ends, so the full length uncertain; minimal lengths were measured as follows: UF 15761-22588, 3.65 cm; UF 15761-22589, 3.28 cm; UF 15761-

22590, 2.97 cm). Individual flowers preserved in multiple planes of symmetry suggesting a whorled or spiral floral arrangement. Flowers variably spaced and may be preserved in an alternate or opposite orientation to their nearest neighbor. Individual flowers varying from ~1 to

1.5 mm in diameter and ~1 mm tall. Flowers unisexual; with only female morphological features visible. Individual flowers preserve 3-5 stigmas (exact number unclear).

Discussion—This species also occurs in the Kisinger Lakes flora and likely in the Green River flora (Cockerell, 1925; Brown, 1929), but its systematic affinities remain uncertain. Cockerell

(1925) tentatively assigned a morphologically similar fossil specimen from the Roan Mountains of Colorado (Eocene Green River Formation) to the Clethraceae and established the formal binomial Clethra? lepidioides (Cockerell, 1925). The raceme described by Cockerell (1925) as

Clethra? lepidioides (along with others from the Green River Formation) is larger and fuller than the Blue Rim specimens. Cockerell (1925) described the globose fruits as 2.3 mm in diameter, which is larger than the 1 to 1.5 mm of the Blue Rim specimens. However, it is possible that the

Green River material is representative of a more mature specimen, which would explain the larger fruits. Extant Clethra specimens were examined in the UC (Berkeley) herbarium (July

2016) and they did not match the fossil specimens. Clethra flowers and fruits are pedicellate

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rather than sessile, and they often have a long style rather than bearing separate styles like the fossils.

Arecaceae often have small flowers on a spike. One hypothesis to consider is that these specimens are the female flowers of Phoenix windmillis. Whereas the overall morphology is consistent with the pistillate flowers of modern Phoenix, the size is incongruent. The female flowers on extant Phoenix are significantly larger, around 4 mm across and 3 mm tall (DeMason et al., 1982; Dransfield et al., 2008), as compared to the 1 to 1.5 mm diameter flowers on the fossil specimens. Other palms with similarities include Sommieria leucophylla Becc. which is a short palm of the forest undergrowth in western New Guinea. The pistillate flowers of

Sommieria are globular with three sepals, petals, and stigmas (Dransfield et al., 2008), whereas these fossils appear to be gynoecia lacking obvious, distinct perianth. Biogeographically this genus seems unlikely to correspond to this fossil, however a more widely dispersed, but related genus may be worth considering. Other extant families considered for the placement of “Mini

Spike” included Araceae, Piperaceae, and Primulaceae. Araceae have indeterminate inflorescences that form a spike with many small flowers (Zomlefer, 1994; Judd et al., 2008).

However, the spikes in most modern Araceae are much broader and fleshier than was observed in the fossil material. Piperaceae also have spicate inflorescences with small flowers, but the spikes of modern Piperaceae are usually much thicker with a more dense arrangement of flowers than is present on the fossils (Zomlefer, 1994; Judd et al., 2008). Fruits of Myrsine in the

Primulaceae (Ericales) look similar; however the calyx is persistent on extant Myrsine fruits

(Zomlefer, 1994; Judd et al., 2008), which is not true of the fossils.

Morphotype—“Sunburst” (Figs. 3-2A-M; 3-3A-G; 3-21E).

Family—Salicaceae Mirb.

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Tribe—Homalieae Dumort.

Specimens—

Blue Rim. Open: UF 15761-22607, 22658, 22662, 22718, 22719, 22720, 22721, 22722,

22723, 22725, 22726, 22728, 22773, 30912, 30974, 30993, 31010, 48590; UF 15761N-43968,

57176, 57376, 57377, 57378, 57379, 57380, 57381, 57382, 57383, 57384, 57385, 57386, 61396,

61407 (?), 61443, 61480, 61485; UF 15761S-57909, 57912, 57928; UF 19337-57984, 58002,

58017, 58031, 58050, 58067, 58089, 61584; UF 19338-58279, 58285, 58286. Closed: UF

15761-22606, 22722, 22725, 22727, 30988, 30989, 48502 (?), 53544 (?); UF 15761N-57381,

57504, 61373 (?), 61406, 61440, 61447, 61450 (?), 61469, 61484 (?). Fruiting: UF 15761-22722,

22800 (?), 48507.

Kisinger Lakes. UF 19374-60361; UF 19376-60014, 60026; UF 19377-61625.

Description—Flowers bisexual, radial. Tepals (likely sepals) 8, valvate, connate at base only.

Tepals average 6.0 mm long (SD = 0.8 mm, Range: 4.0–7.3 mm) by 1.2 mm wide (SD = 0.3 mm, Range: 0.6–1.7 mm) for an average length to width ratio of 5.4:1 (n =109 from ~37 specimens). Stamens numerous (~50–100); filaments distinct. Filaments average 4.0 mm long

(SD = 0.5 mm, Range: 2.6–4.9 mm, n = 78 from 16 specimens), possibly in fascicles. Anthers globose to subglobose, averaging 0.3 mm long by 0.3 mm wide with an average length to width ratio of 1.1:1 mm (n = 31 from 12 specimens). Ovary superior, averaging 5.7 mm in height and

4.1 mm in width (n = 2). Separate elliptical nectary glands present at the base of each tepal averaging 0.7 mm long by 0.4 mm wide (n = 19 from 7 specimens). Pedicel present.

The in situ pollen is tricolpate and prolate with polar length averaging 17.7 µm and the equatorial width averaging 12. 6 µm (n = 5). The colpi do not extend all the way to the poles and average 13.4 µm long (n = 4). Exine is reticulate/semitectate. Exine is smooth along the thick

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colpi margins which are ~2.0 µm wide (n = 4). Reticulation is much finer along the colpi margin with lumina averaging 0.16 µm (n = 9) and coarser away from the colpus with lumina averaging

0.86 µm in longest dimension (n = 13).

Discussion—The “Sunburst” flower morphotype is relatively common in the lower horizon at

Blue Rim, and occasionally found at Kisinger Lakes, but it has not been observed in numerous collections from the Green River Formation. The above description, including the measurements of tepal, filament, and anther size, is based on specimens from both the Blue Rim and Kisinger

Lakes sites. The flowers are preserved in various orientations in the sediment. Observations suggest the corolla and androecium are fused and this composite structure detached from the rest of the flower before being deposited. Transversely compressed specimens consistently lack the receptacle and gynoecium and appear to have torn away from the rest of the flower, such that the center of the preserved portion of the flower is a void filled with sediment. These show a single whorl of eight tepals (rather than four sepals and four petals), which contain elliptical impressions interpreted as nectariferous glands, on their abaxial surfaces. Especially when both the part and counterpart are present, it is clear that the nectaries are 3-D structures. They are often preserved as depressions on one part that maybe filled with dark (possibly organic) matter and slightly raised pads on the counterpart. These are interpreted as nectar glands.

The tepals are all approximately equally developed with no obvious differentiation into petals and sepals. Often the ring of tepals and stamens has split open. It appears that these specimens were originally cup shaped (a hypanthium of fused perianth) and the perianth popped open and was shed like a sleeve. The stamens have globose anthers and are likely in fascicles that are fused at the base. There is a dark ring on some specimens (e.g., UF 15761-48590) that suggests the attachment point for the numerous stamens. It was challenging to estimate the

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number of stamens as many lie on top of or underneath the tepals (depending on whether the abaxial or adaxial side is facing upright). Additional techniques including CT scan may be able to resolve this question. The presence of nectar glands suggest that these flowers were insect- pollinated; however, little is known about the pollination syndromes of the genera formerly assigned to Flacourtiaceae (Sleumer, 1980; Judd, 1997).

The transversely compressed specimens have been matched to laterally compressed specimens in which only three or four of the tepals are visible, some with intact ovaries. The laterally compressed specimens of “Sunburst” show a rounded to truncate base that is decurrent to the junction with pedicel. The pedicel, when preserved, is fused at the base, relatively stout and can be slightly longer than the flower itself. A few laterally compressed specimens preserve a bulbous superior gynoecium. The ovary tends to break off easily and preserves several fused carpels (style remnants are occasionally preserved).

Additionally, a few undescribed specimens from the (Willwood Formation) in the

Bighorn Basin of Wyoming from the Paleocene Eocene Thermal Maximum (PETM) have been recovered that show strong similarities to these specimens. However, the tepals on those specimens, with an average length of 7.8 mm (SD = 0.9 mm, Range: 5.8–9.2 mm) are much longer than the flowers from the Blue Rim and Kisinger Lakes sites. Width is comparable with an average of 1.1 mm (SD = 0.2 mm, n = 22 from 5 specimens). Length to width ratio averages

7.1:1. The PETM specimens have filaments preserved, but rare anthers and no in situ pollen

(which excludes the opportunity for a palynological comparison). An isolated stamen was also recovered at the same site as the flowers in the Bighorn Basin. However, it is also larger than any of the anthers preserved in the flowers from Blue Rim or Kisinger Lakes. Based on the material available, the PETM specimens in the Bighorn Basin might be congeneric, but do not appear to

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be the same species. However, if additional specimens with the diagnostic characters of the Blue

Rim and Kisinger Lakes specimens are found in PETM sediments of the Bighorn Basin then the age and geographic range of this taxon would be extended.

Systematic Considerations. Few angiosperm families have small flowers with eight equal perianth parts in a single whorl, numerous stamens, and prominent nectaries. The fossils have eight individual nectary glands preserved as raised cushions of a similar size and shape on the base of each tepal. The presence of nectaries in a flower and whether they are differentiated into a number of individual glands or presented as continuous structure, such as an annual ring, is taxonomically significant (Bernardello, 2007).

The perianth merosity, androecium, and nectary characters in conjunction with the reticulate, tricolpate pollen indicate that the fossil flowers probably represent a eudicot. The numerous stamens indicate the fossil flowers are not a member of the asterid clade. However, there are many families among the basal eudicots and rosids that must be considered even though this combination of characters seems unusual. Character searches were conducted in Meka

AngioFam using just the floral characters and Delta Intkey using both the floral and pollen characters. The results of these searches included several families with multiple features in common with the fossil material including Ranunculaceae, Berberidaceae, Crassulaceae,

Saxifragaceae, Lythraceae (including Sonneratiaceae), Malvaceae s.l., Passifloraceae, and

Salicaceae s.l.. These families were compared in more detail with the fossils, with particular attention to the presence or absence of nectaries which often is not fully coded in these keys; a separate survey of nectaries was referenced (Bernardello, 2007). In that work, three families

(Paeoniaceae, sepal; Berberidaceae, petal; and Ranunculaceae, petal) were identified as having

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nectaries on the perianth and were also compared to the fossil material (Bernardello, 2007).

Several families could be rejected based on criteria summarized below.

Members of Ranunculales, including Berberidaceae and Ranunculaceae, have features in common with the flowers. Berberidaceae flowers are bisexual, radially symmetrical with a superior ovary and occasionally have 4 petals and 4 sepals, and stamens can be numerous as observed in the fossil specimens (Judd et al., 2008). The inner petals sometimes produce nectar; however, there are no true nectar glands as observed in the fossils. However, Berberidaceae flowers are more commonly 3-merous with multiple whorls of perianth. Petals tend to be short and broad and anthers elongate, not globose like the fossil flowers (Judd et al., 2008).

Ranunculaceae flowers share some features with the fossil morphotype including radial symmetry, a superior ovary, often having tepals or having petals that produce nectar on the base, and numerous stamens with distinct filaments (Judd et al., 2008). However, extant

Ranunculaceae pollen is different from the in situ fossil pollen in that the exine is usually granular or papillate rather than reticulate (Wodehouse, 1936).

Members of extant Crassulaceae, Paeoniaceae, and Saxifragaceae (Saxifragales) also share features with the fossil specimens, but are generally 5-merous and do not have numerous stamens. Crassulaceae usually have small to medium sized, regular flowers with a superior ovary. Floral nectaries are present. Similar to the fossil specimens, the petals can be joined basally, but the stamens are usually free. However, most members of Crassulaceae have 4 or 5 sepals and petals and just 4-10 stamens (Judd et al., 2008), which is divergent from the fossil material. In addition, most extant Crassulaceae species reside in very arid environments, which does not match with the other plants known from Blue Rim. Paeoniaceae have nectaries

(surrounding the gynoecium as a nectary disk), numerous stamens, and many species have a

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superior ovary. There can be 8 petals, however, the flowers are typically quite large, unlike the fossil specimens. Members of Saxifragaceae also have nectaries and the petal and sepal number can be 4, although 5 is most common. The ovary is usually half-inferior. The petals in many

Saxifragaceae are clawed, unlike the fossil flowers (Judd et al., 2008). In examining these families in detail, the fossil material did not fit cleanly within any modern Saxifragalean group.

Modern Lythraceae (Myrtales) have wrinkled petals, which do not appear to be present in the fossils. It is possible that the tepals on the fossil specimens, represent the sepals in Lythraceae and the petals have been lost. Lythraceae also shares the characters of bisexual flowers, numerous stamens, and a superior ovary with the fossil specimens (Judd et al., 2008). Lythraceae often has nectaries, but they are found at the base of the hypanthium, rather than at the base of each perianth unit.

A few species in Malvaceae s.l. resemble this fossil flower morphotype in having only one perianth whorl (most have separate sepals and petals) and nectary patches on the lower part of the calyx or corolla, but the other characters are not in agreement with the fossils. The nectaries on the inner calyx in Malvaceae are composed of discreet regions of densely packed glandular hairs rather than full 3-D pads as found in the fossils. Anther shape is also different between Malvaceae and the fossil specimens. The fossils consistently have 8 perianth parts, whereas Malvaceae frequently have a distinct 5-merous calyx and corolla (Stevens, 2001 onward). Furthermore, Malvaceae pollen is frequently spheroidal and spiny with some reticulate taxa in the Grewioideae, but the details of the exine sculpture do not match with the in situ fossil pollen (Christensen, 1986; Naggar, 2004; Mambrín et al., 2010; Righetti de Abreu et al., 2014).

Both Passifloraceae and Salicaceae sensu lato (Malpighiales) have reticulate, tricolpate or tricolporate pollen in common with the fossil material. Salicaceae sensu lato commonly have

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bisexual, radial flowers with a superior ovary. Members of Salicaceae can have numerous stamens; Passifloraceae usually has 5 stamens. The tepal shape of the fossils matches well with modern Passifloraceae. There are a group of small Passiflora species that are small in size and generally have 5 sepals, but can have up to 8 (K. Porter-Utley, personal communication, June

2012). The nectaries in Passifloraceae are usually on the leaf petiole, rather than associated with the perianth, which is divergent from the prominent position at the base of the perianth in the fossils. Salicaceae typically has a nectary disk of separate glands. Anthers in the fossils are globose, which matches well with many genera of Salicaceae, but not Passifloriaceae where the stamens are elongate and on a stalk. Based on these observations, genera within Salicaceae warranted further consideration.

Assignment to Salicaceae s.l. As currently circumscribed, Salicaceae is composed of three subfamilies Samydoideae Reveal, Scyphostegioideae Reveal, and Salicoideae Arnott

(Chase et al., 2002; Sun et al., 2016). Samydoideae have theoid teeth and the filaments are often connate and form a tube. The leaves in both Scyphostegioideae and Salicoideae have salicoid teeth. Scyphostegioideae is monotypic with the only species found in Borneo. Flowers of

Scyphostegia borneensis are 3-merous unlike these fossils. Salicoideae is comprised of over 900 species in 40 genera throughout the world (not found in New Zealand). Pollen of this clade is usually tricolpate or tricolporate, except in Populus in which it is inapeturate (Stevens, 2001 onward). Based on these characters, Salicoideae is the best match to these fossils.

Salicoideae is composed of six tribes: Saliceae Reichenbach, Scolopieae Warburg,

Abatieae Bentham & J. D. Hooker, Prockieae Endlicher, Bembicieae Warburg, and Homalieae

(R. Brown) Dumortier (Stevens, 2001 onward). The tribes Scolopieae, Homalieae, Prockieae, and Bembicieae all have stamens with small, globose anthers (Chase et al., 2002). Saliceae

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includes the speciose genera Salix, Xylosma, and Populus. The perianth is often absent in the flowers and the primary venation of the leaves can be palmate or with two prominent basal secondaries (e.g., Populus, Stevens, 2001 onward; Chase et al., 2002). Stamens can be numerous in Scolopieae, but the perianth is composed of separate whorls, unlike the fossils (Chase et al.,

2002). Abatieae only includes two genera with a total of 10 species, but only 4-5 sepals are present in the perianth (Stevens, 2001 onward; Chase et al., 2002). Members of Prockieae have many stamens, but flowers usually have a distinct calyx and corolla and lack nectary glands

(Stevens, 2001 onward; Chase et al., 2002). Bembicieae is not a very diverse tribe with only 1 or

2 species in a single genus and has a distinct calyx and corolla (Stevens, 2001 onward; Chase et al., 2002). Members of Homalieae are widespread across in the pantropics. Flowers can be 4 to 8 merous and the perianth is often composed of just tepals. Based on the characters of each tribe, the fossil material fits best within Homalieae (Stevens, 2001 onward; Chase et al., 2002).

Morphotype—“Poofball” (Figs. 3-4A-I; 3-5A-E; 3-6A-F).

Order—Poales.

Specimens—Full infructescences: UF 15761-22580, 22582, 22586, 22587, 22738 (?), 30964; UF

15761N-43930 (?), 44000 (?), 57293, 57424, 57676, 57678, 57679, 57683, 57689, 57691, 57693

(?), 57694 (?), 57698, 57699, 57700, 57778, 57781, 57783, 61366 (?), 61425 (?), 61448; UF

15761S-57812, 61517; UF 19225-57073 (?); UF 19337-57993, 69735; UF 19338-58282.

Isolated subunits: UF 15761-22796, 30921, 31052, 48475, 48478; UF 15761N-57325 (?), 57334,

57677, 57681, 57682, 57684, 57685, 57687, 57688, 57692, 57695, 57696, 57701, 57702, 57703,

57704, 57705, 57706, 57707, 57708, 57709, 57710, 57715 (?), 57721, 57731 (?), 57734 (?),

57736, 57763 (?), 57784, 61439, 61462; UF 15761S-57922, 61502, 61508 (?).

Description—

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Macrofossils. Inflorescences/infructescences globose to ovoidal 2.4-4.2 cm in diameter, composed of numerous (estimated more than 50) sessile units presumed to be florets(?). The largest subunits are 5 mm by 2 mm. Isolated subunits preserve up to three stamens. Pedicels are present, but rare (Fig. 3-4D).

Pollen. The in situ pollen was viewed by epifluorescence, light microscopy, and scanning electron microscopy. The pollen is monoporate without an annulus. Pollen grains are small with a grain measuring 10 by 12.5 µm. The pollen has fine granules/papillae evenly dispersed across the surface. Overall it is small, ulcerate, with granular to scabrate exine sculpturing (elements less than 1 µm in diameter).

Discussion—

Macrofossils. These distinctive, large globose heads were found mostly in a single quarry (UF 15761) at Blue Rim. A specimen of this morphotype is also in the collections of the

Burke Museum from the same Blue Rim quarry. It is somewhat unclear what these specimens represent in the plant body. They have features that could define them as a flower or a multiple/aggregate fruit. However, they are most likely representative of a globose inflorescence based on the presence of intact stamens with in situ pollen. Initially, it was unclear as to whether the isolated subunits were from the large globose heads, but they match in size and shape of the subunits and bear the same kind of pollen indicating that they represent the same plant. Because of the strong compaction, the details of individual florets are difficult to discern in the complete heads, but some disaggregated specimens show single seed-like structures and up to three stamens.

Pollen extraction. Pollen from specimen UF 15761-2286 was removed from an anther with a needle and treated with 20 drops of 10% KOH solution over three minutes, and then

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washed with distilled water. No further treatment was needed prior to viewing via LM and SEM.

The method to extract the pollen from UF 15761N-57784 included the following: A piece of anther material was removed and placed in a small plastic petri dish with a drop of 49% HF for

24 hours. After 24 hours, this was diluted with multiple rounds of distilled water and the pH was tested until it was neutral. Most of the water was drained and a few drops of 5% KOH were added. After a few seconds, when color leaching was observed, the petri dish was flooded with distilled water to halt the reaction. The distilled water was changed out multiple times (while viewing the specimen under the dissecting scope to make sure it was not lost) until the pH was neutral again. Ultimately this was transferred to a glass slide where the presence of pollen was confirmed using LM and then to an aluminum stub for SEM viewing.

Systematic affinities. The taxonomic affinities of these specimens were first examined with attention to the macroscopic characters without consideration of the pollen. This suggested multiple families across the angiosperms including: Alismataceae, Smilacaceae, Pontederiaceae,

Ranunculaceae, Platanaceae, Altingiaceae, Euphorbiaceae, Moraceae, Myricaceae, Malvaceae, and Poaceae.

The individual subunits are similar to extant Poaceae flowers. However, the anthers in extant Poaceae are deeply sagittate, and that was not observed on the fossil specimens. Staminate grass flowers typically have 1 to 3 stamens with long, distinct filaments (Hutchinson, 1964,

1967; Cronquist, 1981; Zomlefer, 1994; Judd et al., 2008). Crepet and Feldman (1991) documented grass fossils from the Paleocene/Eocene Wilcox Formation in western Tennessee.

One of the isolated spikelets with two glumes/bracts and two florets figured by Crepet and

Feldman (1991) resembles the isolated subunits of the Poofball morphotype. In situ pollen was also described from the Wilcox material as monoporate with an average diameter of 16 µm. The

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surface texture of the grains was composed of single small granules and the circular aperture was

~2 µm in diameter (Crepet and Feldman, 1991). Poaceae evolved in the Late Cretaceous (Prasad et al., 2011; Strömberg, 2011), so was certainly widespread by the early Eocene. However, the macrofossil and palynoflora record of the family is poor.

Upon examination of the in situ pollen, all of the families initially considered based on the macrofossil characters alone (including Poaceae) were eliminated because the pollen characters did not match. The monoporate pollen helps to narrow the potential affinities of the pollen to the monocots. The porate, rather than colpate, aperture eliminates many families from further consideration and draws our attention to the order Poales. Although ulcerate grains with similar ornamentation occur in the grass family, Poaceae, it is unlikely to represent that family because the pores of the fossil pollen do not have an annulus. The grass genus Pariana is an exception in that it lacks an annulus, but the surface sculpturing is not similar to the fossil pollen, the pore is better defined, and the overall size of the pollen grains is also larger compared to the fossil pollen (Skvarla et al., 2003). The fossil pollen also has a distinctive rough texture, but most wind-pollinated taxa (including Poaceae) usually have a smooth texture. (Hutchinson, 1964,

1967; Cronquist, 1981; Zomlefer, 1994; Judd et al., 2008).

The characters of the in situ pollen (including its small size, exine sculpturing, and presence of one pore without an annulus) were helpful in eliminating many of the families considered by just examining the macrofossils. Luo et al. (2015) examined 19 pollen characters for 120 taxa in 71 families spanning all orders of monocots. The four most straightforward characters included in their analysis and applicable to the fossil in situ pollen were: size

(diameter of the longest axis), aperture number, aperture shape, and the presence or absence of an annulus. The Blue Rim “Poofball” pollen is small (long axis ~10-12 µm) with one porate

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aperture without an annulus. Of the 120 monocots and 16 outgroups examined by Luo et al.

(2015), seven genera had all four characters in common with the fossil: Amborella, Cyclanthus,

Juncus, Pandanus, Prionium, Thurnia, and Typha. Amborella was an outgroup and its flowers are nothing like the globose heads observed at Blue Rim so it was not considered further.

Cyclanthus (Cyclanthaceae) and the other genera in the family have a spadix-like inflorescence, which is not true of the fossil material. Juncaceae (including Juncus) flowers are usually bisexual

(occasionally unisexual) with 2 whorls of three perianth parts, usually 6 stamens (occasionally

3), and a gynoecium of 3 fused carpels (Jones et al., 2007). However, the pollen is released in tetrads (Munro and Linder, 1997), unlike the fossil. Pandanus (Pandanaceae) pollen is similar to the fossil material in that it is dispersed in monads, is small to medium sized, has a simple, non- annulate pore, and can have a scabrate exine (Furness and Rudall, 2006). However, the flowers of Pandanus are not a match with the fossil material. The staminate flowers in Pandanus (plants are dioecious) are larger and more elongate than the fossil specimens and surrounded by large bracts (Dahlgren et al., 1985). Thurniaceae (including Prionium and Thurnia) has pollen with a pore at the proximal pole with a granular/scabrate exine; the pollen is also small, but generally does not match with the fossil material. The flowers of Thurniaceae have two whorls of three tepals, usually 6 stamens (occasionally 3) and a gynoecium of 3 fused carpels (Jones et al.,

2007). Inflorescences in Prionium are ~1 m long and not in globose heads, but Thurnia can have globose inflorescences (Dahlgren et al., 1985). Species of Thurniaceae are wind pollinated, aquatic herbs. However, the pollen is borne in tetrads (Munro and Linder, 1997), which was not observed in the fossil material. Typha (Typhaceae, Poales) plants are monoecious and the flowers form on a dense spike, which does not match the fossils. Of the taxa that were similar

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from the Luo et al. (2015) analysis, Thuria was the only taxon coded with a tectum sculpture similar to the fossil grains (areolate).

A search on Delta IntKey using both the macrofossil and in situ pollen characters

(flowers aggregated in inflorescences, fertile stamens present, androecium number = 3, pollen grains apeturate, pollen grains with 1 apeture, pollen grains ulcerate, ulcus without an annulus) output 8 results. Of these Burmanniaceae, Myristicaceae, Orchidaceae, and Typhaceae were eliminated due to other characters that were not in agreement with the fossil material. This left

Sparganiaceae (now in Typhaceae), Restionaceae, Juncaceae, and Cyperaceae. These families overlapped with those identified from the pollen search (above) alone.

The inflorescences of Sparganiaceae (now in Typhaceae) can be clustered in globose heads (plants are monoecious, Dahlgren et al., 1985), but they look like just clusters of stamens without the bract-like structures or gynoecia observed in the fossils. The pollen of Restionaceae is also monoporate (Ladd, 1977; Linder and Ferguson, 1985) and the tribe Restionaeae does not have an annulus around its pore (unlike the tribe Anarthrieae). The inflorescences are usually arranged with flowers in spikelets; the flowers are often unisexual and in an axis of a bract

(Dahlgren et al., 1985). Flowers of Restionaceae typically have tepals, three stamens, and are wind pollinated. The male flower of species of Restio has similarities to the fossil specimens.

The cyperid clade (Cyperaceae, Juncaceae, Thurniaceae) within the order Poales has ulcerate pollen and was also considered (Luo et al., 2015). The floral structure in Cyperaceae is more reduced than the other two families in the cyperid clade (Simpson, 1995; Jones et al.,

2007). Inflorescences in Cyperaceae are composed of a few to many spikelets with one to many glumes/scales per spikelet that can be either bisexual or unisexual (Kearns et al., 1998). The fossils appear unisexual. The perianth in Cyperaceae flowers is often absent, but may have

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bristles or scales (Simpson, 1995; Jones et al., 2007). Cyperaceae flowers usually have three stamens (Kearns et al., 1998). The pollen is released in pseudomonads (all 4 of the cells develop at first, but then 3 of the 4 grains degenerate,Simpson et al., 2003). Some genera of Cyperaceae have a capitalum/head-like/globose inflorescence and unisexual flowers including:

Bisboeckelera, Calyptrocarya, Cephalocarpus, Diplacrum, Kyllinga, Mapania, Oxycaryum,

Rhynchospora, and Schoenoplectus (Kearns et al., 1998). The pollen of some extant species of

Mapania does not match the fossils as it has a large, prominent ulcus and a reticulate exine

(Simpson et al., 2003). Dave Simpson (personal communication, Nov. 2016) felt that the fossil inflorescences looked similar to the subfamily Mapanioideae in the Cyperaceae. However, the pollen was not as good of a fit. The fossil pollen is rounded, similar to the mapanioids (rather than pear-shaped in the non-mapanioids), but the exine is more granular in the fossil material

(Dave Simpson, personal communication, Nov. 2016). Members of Cyperaceae are distributed worldwide including temperature regions and often prefer moist habitats (Kearns et al., 1998;

Smith et al., 2009b).

Phylogenetic analyses have concluded that the base of Poales originated in the Early

Cretaceous (~118.8 Ma) with modern families, including Cyperaceae (~82.3 Ma), first evolving in the Late Cretaceous (Linder and Rudall, 2005; Bouchenak-Khelladi et al., 2014). Early diverging members of Cyperaceae are thought to have preferred open and dry habitats, however ancestors of select tribes adapted to wet environments starting in the early Eocene (Bouchenak-

Khelladi et al., 2014).

Morphotype—“Tiny 5-petal” (Figs. 3-7A-H).

Specimens—UF 15761-22584, 22730, 30692 (?), 30934, 30975 (?), 30976 (?); UF 15761N-

57267, 57299, 57300, 57301, 57305, 57306, 57307, 57309 (?), 57310, 57313, 57314, 57319,

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57327, 57328, 57338 (?), 57386 (?), 57396 (?), 57423 (?), 57718 (?), 57719 (?), 57720, 57722,

57723, 57725, 57726 (?), 57727 (?), 57730 (?), 57331 (?), 57732, 57733, 57740, 57741, 57742

(?), 57743 (?),57746 (?), 57747, 57748, 57749 (?), 57754, 57755, 57759, 57760 (?), 57761 (?),

57764, 57769, 57770, 57771, 57772, 57773, 57774, 57775, 57779 (?), 57780, 57785, 61443; UF

15761S-57902, 57915, 57917 (?), 57920, 57927, 57931; UF 19225-56373 (?), 57054, 57091 (?);

UF 19337-61538 (?).

Description—Flowers appear radially symmetrical, ~6-7 mm in diameter, pedicellate. Pedicel at least 2.5 mm long (e.g., 15761N-57423), ~0.5-0.6 mm wide near junction with flower. Flowers with a thickened, rim-like center ~2 mm in diameter, likely part of a 5-part gynoecium. Tepals five, elliptic, and striated, each with “marginal vein” and “midvein.” Tepals ~1 to 1.3 mm wide and nearing 3 mm in length. Stamens present, at least 5, likely 10; anthers ~0.8 to 1.5 mm long by ~0.5-0.7 mm wide, filaments up to 2 mm long.

Discussion—The perianth on these small flowers is almost always truncated (or folded distally) and rarely fully preserved. Small, delicate perianth parts are likely to be ripped or folded during transport and deposition. Five, six (e.g., 15761N-57423), and eight (e.g., 15761N-57754) stamens were counted on individual flowers, suggesting the flowers probably had 10 stamens.

The other stamens are likely buried in the sediment or were ripped off/fell off the flower prior to deposition. Furthermore, the flowers are often preserved in clusters, making it difficult to determine which stamen is connected to which flower.

Even though a specific taxonomic affinity cannot be assigned, these flowers likely belong to the Pentapetalae D.E. Soltis, P.S. Soltis & W.S. Judd clade (Cantino et al., 2007).

Morphotype—“Cup-like flower with tiny stamens” (Figs. 3-8A-G).

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Specimens—UF 15761N-43971, 43976 (?), 57297 (?), 57744, 57765 (?), 57766 (?), 61409; UF

19225-54549, 54577, 57029, 57039 (?), 57049; UF 19337-58001, 58003 (?), 61553.

Description—Pedicellate flowers (longest pedicel observed ~8.5 mm, 15761N-61409). Most flowers laterally compressed. Flower cup shaped, ranging from 3-7 mm wide. Perianth not well preserved, up to ~4.5 mm long. Stamens present, tightly packed, at least 30 per flower, anthers tiny (up to 1 mm long, less than 0.5 mm wide).

Morphotype—“Petals with central vein” (Figs. 3-9A-I).

Specimens—UF 15761-22731, 22737, 30980 (?), UF 15761N-57127 (?), 57265, 57298, 57312

(?), 57318 (?), 57320 (?), 57330 (?), 57332, 57333, 57340, 57348 (?), 57495, 57716 (?); UF

15761S-57910, 57911, 57932 (?); UF 19225-52014 (?), 54573, 57037, 57080, 57099; UF 19337-

57997, 57998, 58009, 58092 (?), 61549.

Description—Flowers preserved in both transverse and lateral orientations. Flowers radially symmetric, ~10 mm in diameter when preserved transversely. Pedicellate (longest pedicel observed over 6 mm long; 15761N-57265, 57298, 57495), pedicel with prominent vascular strand. Perianth most likely with 6 parts (most specimens with 5 partially preserved, six in

15761-22731, 15761N-57333, 19337-57997). Sepals or petals (only one whorl visible) with a prominent central vein. Veins of lower gauge also present, parallel to central vein; marginal vein sometimes visible. Perianth units 4-6 mm in length and ~2-2.7 mm wide. Perianth units ~elliptic in shape with pointed tips. Perianth attached to central “disk” which is <2 mm in diameter.

Stamens present, tiny (under 1 mm, ~0.7 mm long by 0.1-0.2 mm wide).

Discussion—The anthers on this morphotype are significantly smaller than those on the Tiny 5- merous morphotype. The perianth is also larger in both width and length. In addition, the tepals are wider where they are attached to central part of the flower, whereas they are narrower where

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attached in “Tiny 5-petal.” These flowers have morphological affinities to some flowers in the

Salicaceae. It is possible that this morphotype (central vein) is the same as the previous (cup- like) with the flowers preserved in different orientations because the stamens look similar.

However, some of these specimens are preserved laterally and don’t seem to have the same U- shape indicating they are representative of two different flower types.

Morphotype—“Large stamens” (Fig. 3-10A).

Specimens—UF 15761-30908; UF 19225-52022 (?), 52024, 57043 (?); UF 19225N-61836 (?).

Description—Stamens; filaments >5 mm long, anthers 2-2.5 mm in length by 1-1.5 mm wide.

No other floral parts preserved. At least seven stamens are present (19225-52024).

Discussion—Although no other floral structures are preserved, the size of these stamens is larger than the other unidentified flower morphotypes. The stamens are closest in size and shape to

“Tiny 5-petal” but are larger in all dimensions.

Overall discussion for Part I: Flowers

I also considered the taxonomic affinities of the leaves (e.g., Populus, Serjania, cf.

Pseudosalix, Rhus nigricans, Goweria bluerimensis, plus some unidentified) found at Blue Rim to assess the possibilities of these flowers being the reproductive counterpart to the leaves found there. Extant Populus species are wind pollinated, lack perianth, and the flowers are aggregated in catkins. However, it is not known if the extinct species of Populus have perianth or not. Some extinct members of Salicaceae, including Pseudosalix, do have perianth. Some of the Blue Rim

“stamen clusters” could represent staminate Populus flowers (but it appears that these stamens match with the “Tiny 5-petal” morphotype).

Serjania (Sapindaceae) has hermaphroditic (functionally staminate or pistillate), pubescent flowers (Acevedo-Rodríguez, 1988, 1993; Ferrucci and Acevedo-Rodríguez, 2005;

Ferrucci and Coulleri, 2013). The stamens are of similar size in both flowers or slightly larger in

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the staminate flowers, whereas the gynoecium is larger in the pistillate flowers (Ferrucci and

Acevedo-Rodríguez, 2005; Ferrucci and Coulleri, 2013). These features were not observed on any of the Blue Rim unidentified flowers. Furthermore, extant Serjania flowers are larger than

“Tiny 5-petal”—the Blue Rim morphotype most similar to Serjania—they also often have inner and outer sepals (5) of two different lengths and only four petals (Acevedo-Rodríguez, 1988,

1993; Ferrucci and Acevedo-Rodríguez, 2005; Ferrucci and Coulleri, 2013).

Rhus flowers are pedicellate, small, unisexual (but the male and female flowers often look very similar), hypogynous, with 5 sepals, 5 petals, and 5 stamens (Barkley, 1937; Young,

1972; Gallant et al., 1998; Ghazanfar, 2002). These characters are also similar to “Tiny 5-petal,” but they appear to have more stamens, probably 10, rather than only 5 stamens.

Iodes flowers are small and unisexual (although a rudimentary gynoecium on staminate flowers or a rudimentary androecium on pistillate flowers is possible). Female flowers have a very reduced perianth and large, peltate stigmas. Male flowers have a better developed perianth and the petals can have a long attenuated tip. Anthers in Iodes flowers are typically sessile or with very short filaments (Hua and Howard, 2008;G.W. Stull, personal communication, May

2016). Based on these characters none of the unidentified flowers from Blue Rim are a good match to extant Iodes. The “Tiny 5-petal” morphotype from Blue Rim is worth considering based on the size of the flowers, but the fossils have well-defined, long filaments, unlike extant

Iodes. In addition, Iodes anthers tend to be elongate and they are more oval shaped on the fossil specimens. Pollen of Iodes and other members of tribe Iodeae are porate and echinate. We have not found such pollen yet among these flowers. However, there might be some in the dispersed palynoflora (see Part III of this chapter).

Part II: Fruits and Seeds

Order—Laurales

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Family—Hernandiaceae

Species—Illigera eocenia Manchester and O’Leary (Fig. 3-11A).

Specimen—UF 19296-43861.

Description—This winged fruit has a dark fusiform central body ~6.5 mm long by 4 mm wide.

The pair of wings is incomplete, but the more complete wing is ~13 mm long.

Discussion—Fruits of Illigera were recognized in Eocene strata from western North America

(specifically the Green River and Clarno Formations) by Manchester and O’Leary (2010).

Previously, Macginitie (1969) documented specimens of Illigera eocenia in the Green River

Formation as Ptelea cassioides (Lesquereux) MacGinitie. It is not a common element in the Blue

Rim flora and is only represented by a single specimen from the upper horizon.

Order—Proteales

Family—Platanaceae Lestib.

Species—Macginicarpa sp. (Figs. 3-12A-E).

Specimens—UF 19296-43814, 43858, 43859, 54628, 54629, 58228, 58238, 58264; UF 19297-

43700, 58127, 58128; UF 19337-61569 (?).

Description—The Blue Rim specimens range from 1 cm to 2.1 cm in diameter.

Discussion—For additional description and discussion of Macginicarpa see Manchester (1986).

Order—Vitales

Family—Vitaceae Juss.

Species—cf Ampelopsis rooseae (Figs. 3-13A-F).

Specimens—Fruits: UF 15761-22629, 22632, 22738 (?), 22760, 30946, 30957 (?), 30958,

48506; UF 15761N-43947 (?); UF 15761S-57830; UF 19337-57996; UF 19338-61886. Seeds

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only: UF 15761-26709, 30994; UF 15761N-57345, 61461, 61494; UF 15761S-57797, 57798,

57814; UF 19033-39031(?); UF 19225-52020; UF 19337-61566.

Description—Fruit round to ellipsoidal, ~14 to 18 mm in longest dimension (specimen 15761-

30946 is 17 mm by 12 mm with 10 seeds visible), containing up to 10 seeds. Seeds pyriform, 3.5 mm long, 3.0 mm wide, and compressed dorsiventrally (indicating they were likely less than 3 mm thick), with a pair of ventral grooves that are short (~1/3 length of seed) and apically divergent, and an elliptical dorsal chalaza that is less than 1/3 the length of the seed. Apex of seed rounded, base pointed. Seed surface smooth, non-ornamented.

Discussion—This seed morphology, with paired ventral infolds and dorsal chalaza, is diagnostic for the Vitaceae (Tiffney and Barghoorn, 1976; Chen and Manchester, 2011). In the most complete fruit (15761-30946) 10 seeds are visible, which is unusual for the family; all extant genera tend to have only three seeds or fewer (Judy Chen, pers. comm.). This led us to consider whether the specimen might instead represent a coprolite, but the arrangement of seeds in a radial pattern with their hila directed inward, and the thin outer membrane resembling epidermis seems more consistent with being a fruit. Other fruit specimens, similar in size to the one in question, are incompletely preserved or fragmentary specimens so that the full complement of seeds can only be estimated. However, specimen 19337-57996 is intact and only preserves a single seed. The seed characters of this specimen are not well enough preserved for a full comparison to the specimens with numerous seeds, but the size and shape are similar. The size and morphology of the seeds appears to conform with Ampelopsis rooseae from the Clarno Nut

Beds of Oregon (Manchester, 1994).

Order—Malpighiales

Family—Salicaceae Mirb.

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Genus—Pseudosalix Boucher, Manchester, and Judd.

Specimens—UF 15761N-57595 (?), 57597 (?), 57598 (?), 57599 (?), 57600 (?), 57602 (?),

57603 (?), 57604 (?), 57605 (?), 57606 (?).

Discussion—The fruits of this plant are known from their physical attachment to twigs also bearing Pseudosalix leaves and other twigs with flowers connected with the same kind of leaves, from the Green River Formation (Boucher et al., 2003). The fruits are capsular and when dispersed are very difficult to distinguish from those of Populus. Infructescences of Pseudosalix differ from extant Populus and Salix by being branched (paniculate) rather than strictly racemose. Unlike Populus and Salix, the flowers of Pseudosalix retain a well-developed calyx, as confirmed by pistillate specimens attached to twigs bearing the distinctive leaves, and by associated detached staminate flowers with calyx showing the same venation pattern as the pistillate specimens (Boucher et al., 2003). At Blue Rim, some of the isolated capsules are of size and shape similar to Pseudosalix, but they could also be representative of Populus.

Genus—Populus L.

Species—Populus sp. 1 (Figs. 3-14A-C).

Specimens—UF 15761-22601, 22659 (?), 22661, 22663, 22664, 22665, 22666, 22667, 22668,

22669, 22670, 22671, 22672, 22763, 22777, 22778, 22782, 22783, 22784, 22791, 30906, 30948,

30951, 30979, 48479 (?), 48499, 48503, 48593, 48598, 48612, 48614, 48618, 48620, 48621,

48625 (?); UF 15761N-43967, 57324, 57489, 57498, 57500, 57501, 57503, 57508, 57509,

57579, 57580, 57689, 61388, 61392, 61397, 61407 (?), 61445 (?), 61447, 61468 (?), 61472 (?),

61473 (?), 61488; UF 15761S-57801, 57802, 57804 (?), 57807, 57810, 57811, 57813, 57882,

57895, 57896, 57907; UF 19031-39017; UF 19032-39000; UF 19225-52001, 52013, 54572,

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57077; UF 19225N-61820; UF 19337-57990, 58007, 58008, 58018, 58019, 58022, 58029,

58059, 58083, 58084, 61551; UF 19338-58287, 58288, 61881.

Discussion—These capsules are short (~5-9 mm long), small, and rounded (length to width ratio

1.0:1 to 1.5:1) and resemble the fruits found on infructescences attached to twigs bearing leaves of Populus wilmattae Cockerell from the Green River Formation (Manchester et al., 1986;

Manchester et al., 2006). However they also resemble the somewhat larger fruits of Pseudosalix, known also from the Green River Formation (Boucher et al., 2003). Leaves similar to

Pseudosalix occur in the Blue Rim flora.

Species—Populus cinnamomoides (Lesquereux) MacGinitie (Figs. 3-14D-H).

Specimens—UF 00341-61873; UF 15761-22601, 22602, 22603, 22604, 22785, 22786, 22787,

22790, 22792, 30928, 30929, 30987, 43035, 48494, 48498, 48504, 48595, 48596, 48597, 48599,

48600, 48601, 49823, 49824, 49825, 56313; UF 15761N-43943, 43954, 43959, 43960, 57485,

57487, 57488, 57491, 57492, 57493, 57496, 57497, 57581, 57750 (?), 61384, 61390, 61408,

61475, 61476, 61490; UF 15761S-57800, 57805, 57806, 57808, 57809, 57866 (?); UF 18288-

58193; UF 18289-56298; UF 19225-52007, 52008, 52009, 52010 (?), 52011, 52019, 52020,

52313, 54554, 54555, 54556, 54557, 54558, 54559, 56930, 57021, 57057, 57074, 57075, 57076,

57078, 57079, 57081; UF 19225N-57947, 57948, 57949, 57950, 57951, 57952, 57953, 57954,

57957, 61796, 61798, 61801, 61805, 61806, 61807, 61808, 61809, 61810, 61821, 61822, 61837,

61838; UF 19297-43731, 58122; UF 19337-58000, 57989, 57991, 58023, 58065, 58068, 58085,

58088, 61524, 61532, 61537, 61562, 61568, 61575, 61593; UF 19338-61885.

Discussion—These pedicellate, pyriform capsular fruits have 3 to 4 valves and range from long and linear to slightly larger and wider. They resemble those associated with Populus cinnamomoides at its type locality of Green River, Wyoming (Manchester et al., 2006). These

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fruits are larger (~10-20 mm long) and have a greater length/width ratio (1.6:1 to 1.9:1), than the species treated above. Rarely, the Blue Rim specimens show the valves gaping with some seeds spilling out.

Order—Sapindales

Family—Rutaceae Juss.

Species—Chaneya tenuis (Lesquereux) Wang and Manchester (Figs. 3-11B-E).

Specimens—UF 19296-43815; UF 19297-54351.

Description—Fruit with five calyx lobes. Sepals generally obovate with rounded apices.

Complete sepal on 19296-43815 10 mm long by 4 mm wide. Venation runs the length of the sepal.

Discussion—This fruit, represented only by two specimens, both from the upper horizon at Blue

Rim, corresponds in the morphology and venation of the calyx to the extinct genus Chaneya, known from the Eocene of western North America (including in the Green River Formation and in the Aycross Formation, MacGinitie, 1969; MacGinitie, 1974), the Eocene to Miocene of Asia, and the Oligocene to Miocene of Europe (Wang and Manchester, 2000; Teodorides and Kvacek,

2005; Manchester and Zastawniak, 2007). Specimens of Chaneya tenuis from Kisinger Lakes in northwestern Wyoming are also present in the FLMNH collections including: UF 19376-59754,

59759, 59761.

Family—cf. Meliaceae Juss.

Species—cf. Cedrela sp. (Figs. 3-11F & G).

Specimen—UF 19297-43915 (?).

Description—Seed with an elliptical body and a single extended lateral membranous wing with a rounded distal margin. Wing lacking venation. Seed body 3 by 2 mm, oriented with its long axis

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about 40 degrees from the long axis of the wing. Length of seed including wing 9.5 mm, width including wing 4.5 mm. A narrow flange surrounds the entire circumference of the seed body, in its plane of bisymmetry and extends outward on one side to form the lateral wing.

Discussion—The morphology of this seed matches some seeds that are common but still undescribed from Kisinger Lakes. However, the affinities of this winged seed are still uncertain.

Among conifers, the seed is similar to that of Calocedrus. It is distinguished from Pinaceae by the lack of longitudinal striations on the wing. Similar seeds, with an elliptical seed body and single lateral wing lacking venation occur convergently in several angiosperm families including

Meliaceae (Cedrela), Theaceae (Gordonia), Malvaceae (Luehea, Lueheopsis, Reevesia) and

Oleaceae (Schrebera). It is unlikely to be Cedrela because this specimen and the similar ones from Kisinger Lakes lack the diagnostic intramarginal crease at the distal margin of the seed.

This feature of the extant seeds usually preserves in impression fossils, as documented in the

Oligocene (Meyer and Manchester, 1997) and Miocene (Succor Creek flora, Arnold, 1936).

Family—Anacardiaceae R. Br.

Species—Pentoperculum minimus (Reid and Chandler) Manchester (Figs. 3-11H-K).

Specimens—UF 15761-22593 (?), 22594, 22595 (?), 22596, 22597 (?), 22598, 22599, 22600,

22601, 22634 (?), 22654, 22660, 22703, 22716, 22771 (?), 22776, 22778, 22783 (?), 30969,

30970 (?), 30971, 30972 (?), 30973 (?), 30979, 30984 (?), 30985, 30990, 30992, 48466, 48471,

48474, 48588, 48589, 48602, 56319 (?), 59505, 59506, 59507; UF 15761N-43931 (?), 43946 (?),

43964, 57182, 57192, 57212, 57213, 57214, 57215, 57216, 57217, 57218, 57220, 57221, 57222,

57225, 57226, 57227, 57260, 57286, 57287, 57288, 57289, 57290, 57292, 57219, 57291, 61401

(?), 61446, 61474 (?), 61481, 61493; UF 15761S-57891, 57892; UF 19225-58188; UF 19225N-

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57959; UF 19337-57994, 58049, 58073, 58075, 58076, 61527, 61535, 61548 (?), 61594, 61595,

61596.

Discussion—The endocarps of these fruit are recognized by their rounded pentagonal outlines and the impressions of 5 elliptical apical germination valves. Although these fruits are not permineralized as the type specimens from London Clay (Reid and Chandler, 1933) and others described from the Clarno Formation (Manchester, 1994), the form of the endocarp is distinctive.

As impressions, the Blue Rim specimens preserve a feature that was not seen in the London Clay and Clarno specimens however: the meso- and exocarp are preserved as a brown outline loosely surrounding the more deeply impressed endocarp. Presumably these had a fleshy covering similar to that of extant fruits in the Spondioideae subfamily of the Anacardiaceae.

Family—Incertae sedis

Species—Landeenia aralioides (MacGinitie) Manchester and Hermsen (Figs. 3-10B-G).

Specimens—Flowers: UF 15761-22669, 22735 (?), 22801, 30936, 48485, 48606, 48609 (?),

48613 (?), 59502(?); UF 15761N-57594 (?); UF 15761S-57925 (?); UF 19225-54549, 54551,

54574, 56907, 57003, 57038, 57106; UF 19337-58070, 58071 (?). Fruits: UF 15761-22621,

22623, 22624, 22625, 22627, 22628, 22631, 22633, 22634, 22635, 22636, 22637, 22638, 22639,

22640, 22641, 22642, 22643, 22645, 22647, 22649, 22657, 22717, 26704, 26705, 26706, 26707,

26708, 22734, 30913 (?), 31052, 48486, 48487, 48488, 48489, 48490, 48492, 48619, 49829,

49831, 59501; UF 15761N-43958, 57187, 57612, 57613, 57622, 57623, 57624, 57625, 7651,

57690, 61408, 61493, 61496; UF 15761S-57805, 57817, 57982, 57983, 61500; UF 19225-52000

(?), 52003, 52004, 52005, 52006, 52011, 52023, 54542, 54543, 54545, 54546,54549, 54550,

54552, 54553, 56905, 56906, 56907, 56908, 56909, 56910, 56911, 56912, 56913, 56914, 56915,

56916, 56918, 56919, 56920, 56921, 56922, 56923, 56924, 56925, 56926, 56929, 56932, 56934,

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56947, 56999, 57025, 57047, 57086, 57120; UF 19337-57979, 57980, 57981, 57982, 57999 (?),

58030 (?), 58046 (?), 58066, 59463 (?), 61562, 61584. Seeds: UF 15761-30939, 30941, 30942,

30943, 30949, 48484, 48491, 48613, 49827, UF 15761N-57609, 57610, 57611, 57614, 57615,

57616, 57617, 57619, 57620,57621, 57757; UF 15761S-57799, 57817, 57820, 57822, 57879;

UF 19032-38993, 38994, 39003, 39010, 51199, 51201; UF 19225-52012, 52016, 52017, 52314,

54544, 54547, 54548, 54550, 56341, 56348, 56907, 56917, 56920, 56921, 56935, 56945, 57087,

57088, 57089, 57090, 59494; UF 19225N-61823; UF 19296-58247; UF 19297-43673, 43775 (?),

43913, 43914 (?), 58115 (?), 58119 (?), 58150 (?), UF 19337-57992, 58021, 61572, 61586,

69564; UF 19338-58277; UF 19405-61651, 61658.

Discussion—This genus was established on the basis of fruits first described from the Kisinger

Lakes locality as Carpites aralioides MacGinitie (MacGinitie, 1974). Matching fruits from Blue

Rim, were found to include specimens dispersing elliptical winged seeds and forming an ontogenetic maturation sequence with flowers bearing stamens with striate tricolpate pollen.

Although Manchester and Hermsen (2000) were unable to relate this to a particular modern genus or family, its features including 5-part calyx, nectariferous disk, superior ovary with numerous carpels and single style, are consistent with Sapindales.

Order—Icacinales

Family—Icacinaceae Miers.

Species—Biceratocarpum brownii, now Iodes brownii (Stull et al., 2016).

Discussion—Initially, this was distinguished as an extinct genus of Icacinaceae distinct from

Iodes because of a pair of apical protruding “horns”. However, when the survey of extant Iodes species was broadened, it was found that endocarps of modern Asian species of Iodes can possess the same kind of horns (Stull et al., 2016). Therefore, we now consider these to represent

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this extant genus which is now disjunct between Africa and Asia, but known from numerous fossil occurrences in Europe and North America (Reid and Chandler, 1933; Manchester, 1994;

Pigg et al., 2008; Stull et al., 2016). Although this species is common at Kisinger Lakes and is known from the Green River Formation, it is rare at Blue Rim. See Chapter 5 for a description, figures, and additional discussion.

Species—Iodes occidentalis S.E. Allen, Stull, & Manchester.

Discussion—This is the more common species of Iodes at Blue Rim, and one of the most abundant angiosperm fossils encountered in the fossil assemblage from the lower horizon. See

Chapter 5 for a description, figures, and additional discussion.

Order—Alismatales

Family—Araceae Juss.

Species—cf. Keratospermum (Figs. 3-15A & B).

Specimens—UF 19033-39030; UF 19225-54576 (?); UF 19338-58280 (?).

Description—Loose cluster of seeds ~5.8 cm by ~1.6 cm wide (19033-39030). Seeds small, curved, 2-3 mm long by 1 to 1.5 mm wide. Specific features of seeds not well preserved.

Discussion—Many of these clusters contain multiple seed types. They may represent a coprolite or taphonomic artifact (S.Y. Smith, personal communication, Oct. 2012).

Species—Incerte sedis (Figs. 3-15C; 3-16F-H).

Specimens—UF 18288-58202, 58209, 58213.

Description—Linear cluster of dark seeds ~15-20 mm long by ~5-6 mm wide. Approximately 20 seeds visible (18288-58209). Seeds curved, ~1.6 mm long by ~0.5 mm wide. Seeds with small depressions in a curved line on the broader side recognized by dots of raised sediment where seeds have since been lost.

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Order/Family—Incertae sedis

Species—Lagokarpos lacustris McMurran et Manchester (Figs. 3-15D & E).

Specimens—UF 19297-54243, 58134.

Description—Seed body rounded, ~3 mm in diameter with an ~1.6 cm wing for a total length of

~1.9 cm (19297-54243). One wing only preserved on 19297-58134; ~1.6 cm long, ~5 mm wide with a prominent central vein with secondary veins branching off of this.

Discussion—Lagokarpos lacustris has been found in sites of the Green River Formation in WY,

UT, and CO in addition to localities in Oregon and British Columbia (McMurran and

Manchester, 2010).

Morphotype—“Winged Teardrop” (Figs. 3-17A-C; 3-21H).

Specimens—UF 19225-52021, 57035 (?), 57123; UF 19297-43753, 43916, 43917, 58137.

Description—Winged fruit (or winged seed) with singe pyriform shaped seed in center. Seed 5.5 to 6 mm long by 4 to 4.5 mm wide. There is a single symmetrical wing surrounding the central elliptical seed. Seed has a thickened rim and a bumpy surface (based on the pitted impression).

Wing extends 2 to 4 mm from seed and is pointed on the same end the seed is rounded.

Discussion—This winged fruit is preserved in both the lower and upper horizons at Blue Rim. It is not clear if 19225-57035 is the same morphotype because it is considerably smaller than the other specimens. In that specimen, the seed is only ~3 mm by 1.75 mm with the wing only extending less than 1 mm from seed margin. Specimens 19297-43753 and 19297-43917 have the same seed body, but lack or do not preserve the wing. Similar specimens are occasionally preserved in the Green River Formation (not published to my knowledge). These specimens are similar to, but do not match Dipteronia. They also resemble some seeds in Asclepiadaceae, but the taxonomic affinities remain uncertain.

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Morphotype—“Beach Ball Type 1” (Figs. 3-17D & E).

Specimens—UF 15761S-57818; UF 19337-61552.

Description—Oblong fruit or large seed; 8 to 9 mm in diameter; > 9mm long (broken). Grooved, parallel lines running in long direction.

Morphotype—“Beach Ball Type 2” (Fig. 3-17F).

Specimens—UF 19225-56345, 56987 (??).

Description—Rounded fruit or large seed, ~15 mm in diameter (19225-56345). Central area indented. No defining characteristics present.

Morphotype—“Tiny Winged” (Figs. 3-17G-I).

Specimens—UF 15761N-57335, 57336, 57337, 61425; UF 18288-58205, 58206; UF 19225-

56989, 57103, 57104; UF 19225N-61800, 61801, 61803; UF 19232-52317; UF 19337-61581.

Description—Oval winged seeds or fruits. Individual units are ~3 to ~3.5 mm in length. Width

~2 mm. Central area is ~1.5 by 1 mm in size, surrounded by wing. Possible remnant style on some specimens. Cuticle sometimes present in center.

Morphotype—cf. Calycites ardtunensis Crane (Figs. 3-18A & B).

Specimens—UF 19296-43856, 43857; UF 19297-58133.

Description—Linear seed body ~11 mm long by ~4 mm wide with deep vertical striations (~5 visible, indicating ~10 total). At least three large wings present; wings begin at the apical rim of the striate body. Wings have a midvein with pinnately arising secondaries that form a reticulum.

Discussion—Similar, but more complete specimens of this kind are known from the upper part of Wilkins Peak Member of the Green River Formation at Little Mountain, Wyoming. They show five wings. Crane (1987) placed such fruits from Paleocene and Eocene of Western North

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America in Calycites ardtunensis, a species that he also recognized from the Paleocene of

Scotland. This taxon has similarities to Abelia in the Caprifoliaceae.

Morphotype—“Three carpels” (Fig. 3-18C; 3-21F).

Specimens—UF 19337-61522, 61560.

Description—Pedicellate tricarpellate apocarpous fruit. Each oval body (? locules) are ~3.5 mm by 2.5 mm. The three ellipsoidal bodies are united in a symmetrical, triangular arrangement.

Bodies have a median keel and share a single narrow pedicel (visible with surface renderings from CT scan X-ray data). Style position (whether sharing a common style, or three separate ones) not preserved.

Discussion—One of the specimens (19337-61522) is broken transversely through the fruit, revealing the convex-rounded surfaces of two locule casts surrounded by a thin film of carbonaceous remains presumed to represent the fruit wall. Another specimen (19337-61560) exhibits the same size and configuration but appears to have been exposed along the outer surface of the endocarp, hence showing more clearly the median keel on each of the three carpels. It resembles some Euphorbiaceae and Sapindaceae.

Morphotype—“Two Sectioned Crescents with Tails” (Figs. 3-18D-G).

Specimens—UF 19225N-61835; UF 19337-61520, 61523 (?), 61579, 69288, 69229.

Description—Curved, crescent shaped structures with pointy ends. Individual crescents are widest (~1.5 mm) in the middle and ~4 mm long. Structure has a marginal vein and irregular medial vein extending from tip to tip. The central vein is wavy, but generally follows the curved shape. Possible seed-like structure present in center. Individual crescents frequently clustered together, nested with their curved edges together and the pointy tips sticking out. The largest

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cluster has well over 50 individual crescents (19337-61579). Some crescents preserve a narrow extended tip off one of the pointed ends that increases the overall length by 1-2 mm.

Discussion—Crescents are most likely representative of a fruit, specifically an achene with the infructescence an aggregate of achenes. Aggregates of achenes are found in Alismataceae and

Ranunculaceae among others. These fruits look similar to those of extant Sagittaria, however the fossils have a marginal vein, which is not present in the extant material.

Morphotype—“Spikey Sun” (Figs. 3-18H & I).

Specimens—UF 19225N-57943, 61816.

Description—Central circular to oblong structure, ~3 mm in diameter surrounded by at least 10 narrow “spikes” radiating outward. One of the longest “spikes” is over 1.8 cm long (19225-

61816).

Morphotype—Cluster Type 1 (Figs. 3-16A-E; 3-21I).

Specimens—UF 15761-53543; UF 19225-57072, 57083, 57085.

Description—Aggregates of tiny, winged seeds often with cuticle. Seeds range from ~1.2 to 1.3 mm long by ~0.7 to 0.9 mm wide.

Morphotype—Cluster Type 2 (Figs. 3-19A-C).

Specimens—UF 15761S-57878, 57899, 57900; UF 19225-57051; UF 19225N-61827, 61833.

Description—Scattered seed-like structures, often with little morphological detail. Units are 3-4 mm long by 2-3 mm wide.

Discussion—These specimens are similar to “Tiny Winged,” but that morphotype has a well- defined center (often with organic matter) and wing, whereas these are often all dark and the shape is slightly different than morphotype “Tiny Winged.”

Morphotype—Cluster Type 3 (Figs. 3-19D; 3-21G).

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Specimen—UF 15761N-43956.

Description—Cluster of tiny rounded seeds. Cluster is about 22 mm long, partly hidden in sediment, so not known whether globose or ellipsoidal. Estimated to have more than 100 identical seeds, each seed rounded, ellipsoidal, ca 1.2 mm diameter, with a thin shiny dark layer occasionally preserved.

Morphotype—Cluster Type 4 (Figs. 3-19E-G).

Specimens—UF 15761N-61380; UF 15761S-61514; UF 19225N-61824.

Description—Cluster of linear and circular shaped striated structures. Structures often overlap in cluster. Individual units are 1.5 to 2 mm wide.

Morphotype—Larger Spike (Figs. 3-20A & B; 3-21A-C).

Specimen—UF 19225-57041.

Description—Globose clusters of flowers, borne sessile on an axis, resembling a spike. Flowers

2-3 mm in diameter; entire inflorescence at least 3 cm long. In situ pollen tricolpate with a striate exine. Grains 15-16.5 µm in diameter.

Discussion—This inflorescence is out of order because it was initially thought to be a fern spike and that each “sporangia” was filled with colpate or monolete spores when viewed by transmitted light microscopy. However, upon viewing the “spores” via SEM, it was revealed that they were tricolpate pollen and that this structure is from an angiosperm. Tricolpate, striate pollen is found in the Sapindales, Begoniaceae, Rosaceae, Saxifragaceae, and a few other eudicot families.

Non-Angiosperm Reproductive Structures

Morphotype—Equisetum sp. strobili and whorled “tubers” (Figs. 3-20C-G).

Specimens—UF 15761-22797; UF 19225- 52081; UF 19225N-57935, 57944, 57945, 57946,

61802, 61804, 61822, 61827, 61829, 69006; UF 19297-43752.

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Part III: Dispersed Pollen and Spores

Dispersed pollen and spores can provide different information about the taxonomic composition and paleoclimate of a flora than macrofossils. Many grains are transported significant distances and can provide clues about the surrounding regional flora. Vegetation shifts based on NLRs can show changes in moisture or temperature (Stokstad, 2001) with a climate resolution of ~50 years. For example, fossil pollen has been used to estimate five successive climates in the Eocene with the early Eocene being moist subtropical (Wind River flora), the earliest Middle Eocene dry subtropical (Little Mountain flora), and the early Middle

Eocene with moist, subtropical conditions (Kisinger Lakes flora, Leopold and MacGinitie, 1972;

Roehler, 1992b).

The taxonomic resolution of pollen and spores is usually lower than macrofossils and is often limited with many species, genera, and families having morphologically similar grains

(Mander and Punyasena, 2014). Multiple species may be lumped into a single morphotype

(usually a genus) because they look similar under standard light microscopy. This problem can be partially addressed by using high resolution microscopy techniques and other tools including computerized image analysis (Mander and Punyasena, 2014). However, these methods (e.g.,

SEM) are time consuming and more expensive than standard light microscopy. Other issues that can hamper identification include the lack of comprehensive reference collections—a problem that is more acute in the tropics—and researchers not identifying the same grain to the same clade (Mander and Punyasena, 2014). However, many grains are distinctive, even under light microscopy, and can provide information not otherwise available from the macroflora alone.

Palynologists often use morphogeneric names for most fossil palynomorphs rather than extant names (Nichols, 2010). However, extant names are used in cases where the morphology is very distinctive (e.g., Alnus) or to provide continuity with older literature (e.g., Nichols used

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extant names to provide continuity with Wodehouse when reevaluating the Green River palynoflora, Nichols, 2010). Alnus can have (3) 4 to 6 pores with distinct arci (Nichols, 2010;

Liu et al., 2014); the Blue Rim examples tend to have 5 pores.

Material and Methods

Slides were created from 30 different sedimentary units (12 from the UF 19225/2012 stratigraphic section, all 17 units of the UF 19297/2014 stratigraphic section, plus the UF 19404 channel fill locality). Nine units (UF 19404 [21.5 g]; units 8 [40 g], 13 [30.3 g], 18 [42.9 g] from

2012; and units 1 [25 g], 11 [21.5 g], 12 [20 g], 15 [21.5 g], and 16 [25 g] from the 2014 section) have good or excellent preservation; material from six of those are figured and discussed here

(grams of sediment processed in [ ] brackets after unit number).

Samples were prepared using standard palynological preparation techniques (5 µm sieve) at Global Geolab Limited in Medicine Hat, Alberta, Canada. Slides were made by mixing the extracted pollen with polyvinyl alcohol on a coverslip; when that dried it was flipped and bonded to a slide using clear polyester casting resin (Russ Harms, personal communication, Feb. 2014).

Lycopodium spores were added in known quantity to each slide to aid in future research questions necessitating counting palynomorphs per volume of sediment. The slides from units 8,

9, 13, 14, and 18 from the 2012 stratigraphic section have two tablets of Lycopodium spores. The slides from the other processed units of the 2012 section, the 2014 stratigraphic section, and UF

19404 have one Lycopodium tablet. The tablets were all from Batch 1031 with an average of

20848 (SD = 1546) spores per tablet (Russ Harms, personal communication, Jan. 2015).

Slides were viewed on a Nikon Eclipse E600 microscope. Well-preserved grains were photographed using a Canon EOS Rebel Xsi camera and their coordinates on the slide were recorded along with any observations. For comparison to another mechanical stage, the

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coordinates for the center point of a 1 x 3 inch standard microscope slide on the Nikon Eclipse

E600 are: 36.8 (horizontal axis) by 103.4 (vertical axis).

Pollen grains were identified by comparing to published literature (both fossil and modern), online pollen and spore databases (e.g., http://www.geo.arizona.edu/palynology/; https://www.paldat.org/; http://apsa.anu.edu.au/), and using the reference collection in the paleobotany range of the FLMNH. Most of the taxonomic identifications from units 15 and 16 were made by Morgan Pinkerton, an undergraduate research assistant.

Systematics and Results

UF 19404. Although only part of one slide has been reviewed, this channel fill site low in the section contains an excellently preserved diverse palynofloral assemblage in very fine sand.

This site also includes a diverse leaf flora. Some spores (Figs. 3-22A-H, J, K) are present, along with gymnosperms including representatives of Pinaceae (Figs. 3-22M, N), and numerous angiosperms including grains with affinities to Carya (Fig. 3-23A), Tilia (Figs. 3-23C, D), and

Alnus (Fig. 3-23E). Echinate pollen similar to Icacinaceae (Fig. 3-23H) may be present, but it also looks similar to what Leopold identified as cf. Schoutenia (former Tiliaceae, now

Malvaceae, MacGinitie, 1974). The grains identified as cf. Schoutenia from the Kisinger Lakes flora are ~21.1 µm to ~26.8 µm in diameter (MacGinitie, 1974). Icacinaceae is also represented in the Blue Rim macroflora by leaves and fruits. Hexaporate pollen (Fig. 3-23F) with affinities to

Juglandaceae is also present along with possible Ulmaceae (Fig. 3-23B).

Unit 8-2012. The dispersed palynoflora from unit 8 was preserved in sandstone. Petrified wood was present, but no other macrofossils were preserved in this unit. The pollen includes polyporate specimens with affinities to Chenopodium (Figs. 3-24E, G), Carya (Fig. 3-24A), possibly Asteraceae (Figs. 3-24C, D), and Juglans (Fig. 3-24F). Bisaccate grains of Pinaceae

(Figs. 3-24J-O) is also well represented by at least 15% of the grains on the slide.

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Unit 18-2012. The dispersed palynoflora of this unit was preserved in a fine sandstone with plant hash composed of mostly monocots and fossil wood. Multiple types of trilete spores including ones with similar morphology to Lygodium (Fig. 3-25B, similar to grains found in situ in sorophores of Lygodium kaulfussi Heer, Manchester and Zavada, 1987), Granulatisporites/

Deltoidispora (Figs. 3-25C, D), and cf. Cicatricosisporites dorogensis (Fig. 3-25I, Frederiksen,

1980) are present. Pinaceae, including grains with affinities to Picea (Fig. 3-25K) and Pinus

(Figs. 3-25L, M), are represented. Small, rounded or oblong monosulcate grains are likely representative of one or more monocotyledonous taxa (Figs. 3-26A-G). Tiny reticulate, tricolporate grains are also frequent and may represent Salix (Figs. 3-26O-U). Other tricolpate grains include one with striations with possible affinities to Acer (Fig. 3-26N). Porate grains include ones with morphological similarities to Alnus (Fig. 3-26L), Icacinaceae (Fig. 3-26M),

Betulaceae (Fig. 3-26W), Ulmaceae (Figs. 3-26X, Y), Carya (Fig. 3-26I), and Corylus (Fig. 3-

26V).

Unit 11-2014. This unit preserves petrified wood, in addition to the dispersed pollen and spores, in silt to very fine sand. Spores are common in unit 11 (Fig. 3-27). Pinaceae is represented, but not figured. Angiosperm diversity is lower than some of the other units and includes grains with affinities to Carya (Figs. 3-28A, B) among others.

Unit 15-2014. Unit 15 includes the upper plant horizon, specifically in the area of macrofossil site UF 19297. Sediment ranges from silt to fine sand. The dispersed palynoflora includes spores and pollen of both gymnosperms and angiosperms. Gymnosperms include representatives of Cupressaceae (including Taxodiaceae) ranging in size from ~27-40 µm (Figs.

3-29F-H). Pollen of Cupressaceae has been recognized from other Eocene sites from North

America (e.g., Wodehouse, 1933; Frederiksen, 1980; Nichols, 2010). Pinaceae is likely

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represented by multiple genera as the grains ranged from ~50 to >100 µm (Figs. 3-29I-M).

Grains of Pinus are consistently smaller than those of Picea or Abies (Weir and Thurston, 1977).

Angiosperms include representatives of Juglandaceae (cf. Carya, ~20-30 µm, Figs. 3-30E & F; cf. Platycarya, Fig. 3-30M), Betulaceae (Alnus, ~20-21 µm, Figs. 3-30A, B), Malvaceae (cf.

Tilia, ~15-29 µm), Ulmaceae (cf. Ulmus, ~30-35 µm, Figs. 3-31L, M), Magnoliaceae (~38 µm,

Fig. 3-30L), Aquifoliaceae (cf. Ilex, ~34 µm Fig. 3-30J), possible Myrtaceae (Fig. 3-31E), other

Malvaceae (Fig. 3-32G), and possible Sapindaceae (Fig. 3-30I).

Many of these families, including Pinaceae, Cupressaceae, Juglandaceae, Betulaceae,

Ulmaceae, Aquifoliaceae, Malvaceae, ?Sapindaceae and ?Myrtaceae, are shared with the palynoflora from Kisinger Lakes in northwestern Wyoming (MacGinitie, 1974). It is worth noting that all the ulmaceous pollen from Blue Rim is substantially larger than the 18-22 µm pollen documented from the extinct ulmaceous genus Cedrelospermum Saporta (Manchester,

1989).

Unit 16-2014. Unit 16 preserves representatives of monilophytes, gymnosperms, and angiosperms in fine to medium sand. The gymnosperms included representatives of Pinaceae

(Figs. 3-33H,I, K-O), Cupressaceae (Figs. 3-33C, D), and Ephedraceae (Ephedra, Figs. 3-33E-

G). Specimens assigned to Pinaceae from unit 16 are likely Pinus rather than the other bisaccate pinaceous genera because they are all smaller than 100 µm and have well-developed sacci. Picea and Abies grains are usually larger than Pinus and Abies has a sharper angle between the pollen body and the sacci (Weir and Thurston, 1977). Angiosperm families represented in unit 16 include: cf. Ranunculaceae (Figs. 3-34Q, R), Amaranthaceae (Chenopodium, Figs. 3-35A, B),

Ulmaceae (Figs. 3-34I, J), cf. Fagaceae (Figs. 3-35K-O), Betulaceae (Alnus, Fig. 3-34A),

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Juglandaceae (Carya, Figs. 3-34E, F; Juglans, Fig. 3-34D), Malvaceae (Tilia, Fig. 3-34H), and

Asteraceae (cf. Emilia, Fig. 3-34K).

Discussion

Although the dispersed palynoflora at Blue Rim has only been briefly reviewed, it preserves a different floral composition than the macrofossils. Whereas the leaves (Chapter 2 &

5), reproductive structures (Chapters 3-5), and wood (Chapter 6) reflect the local flora and conditions at Blue Rim the early Eocene, the dispersed pollen and spores are more representative of taxa from the regional flora and higher elevations. The surrounding uplands likely included areas of conifers and more temperate floral elements based on the taxa preserved in the dispersed palynoflora. Species present only in the microflora include: Ephedra, Chenopodium, Alnus,

Carya, Tilia, Asteraceae, and Cupressaceae. Amaranthaceae (represented by Chenopodium-like pollen) and Ephedra indicate the likely presence of more arid plants in the region.

Pollen source area is determined by numerous factors. In general, basin size has a significant effect on the proportion of pollen originating from local or regional sources (Lynch,

1996; Matthias and Giesecke, 2014). For example, larger lakes have more pollen from the regional area, whereas smaller lakes and water bodies often have pollen predominantly from local sources carried by air currents through the trees as pollen transported above the canopy is less likely to be deposited (Matthias and Giesecke, 2014). In forested areas, lakes over 10 ha had pollen from within ~30 to 50 km, small lakes (<10 ha) had source areas on the order of 6 km, whereas ponds (~100 m in diameter) only had pollen from species growing within ~300 to 400 m

(Lynch, 1996). However, in other cases, small water bodies with little local pollen can have a high percentage of pollen from the regional flora (Lynch, 1996). Landscape structure and topography can also limit or enhance pollen transport; pollen can move both upslope or downslope and is often influenced by wind patterns (Hall, 1990; Fall, 1992; Matthias and

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Giesecke, 2014). Pollen rain can include species from plants beyond the basin margin and the regional pollen rain is usually consistent when local elements are removed from a specific site

(Janssen, 1966). The morphology of individual pollen grains is also an important factor which affects the percentage of pollen that stays airborne as the distance from the source tree increases

(Matthias and Giesecke, 2014). Most pollen lands near its source, but it can be transported a significant distance in part due to its low specific gravity (Traverse, 2007).

In general, Pinus can be carried further by the wind than the larger bisaccate grains of

Picea or Abies (Fall, 1992), which may be why it is more common in the Blue Rim microflora.

On average Pinus comprises about 10% of the regional pollen rain and only exceeds 20 percent if pine trees are nearby (Fall, 1992). Although it might seem odd to have possible representatives of herbaceous families in the Blue Rim dispersed palynoflora (e.g., unit 16), present-day pollen from herbaceous families including species of Ranunculaceae and Rosaceae were commonly encountered in pollen traps of the Rocky Mountain region of Colorado (Fall, 1992). The presence of Amaranthaceae and Artemisia (rare at Blue Rim) often indicate a continental climate with cold winters and dry summers (Zhao and Herzschuh, 2009). However, these are not dominant elements in the dispersed palynoflora and could have been transported from a significant distance.

A well-preserved palynoflora can help corroborate a savannah or forested ecosystem based on the presence or absence of grass pollen (Strömberg, 2011). High levels of grass pollen

(>10%) are observed in modern samples collected from grasslands (Hall, 1990; Matthias and

Giesecke, 2014). The monoporate pollen of Poaceae is distinctive and the lack of this in the Blue

Rim dispersed palynoflora corroborates other data indicating Blue Rim was not close to a

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grassland. Forests with pines were certainly present in the regional flora based on the presence of pine pollen in all the samples (Hall, 1990; Matthias and Giesecke, 2014).

Macrofossils of Populus are common at Blue Rim, especially in the lower horizon, but

Populus pollen has not been readily recognized in the dispersed palynoflora. However, in modern experimental studies where pollen was collected in areas where Populus was dominant, it was not a significant component (<2%) of the trapped pollen; it is possible that the experimental studies were collected in low production years (Hall, 1990). However, this pattern was also observed with other taxa including Abies (Hall, 1990). Populus also has a lower sporopollenin content in its exine making it less likely to be preserved in the fossil record

(Traverse, 2007). This is one of the reasons why it is helpful to examine both the macro and microflora, if possible. If one just examines the dispersed palynoflora, taxa restricted to certain elevations or climates, even if they are not representative of the local conditions, are often present, potentially biasing the summary of the floral composition or paleoclimate estimates

(Hall, 1990).

Kisinger Lakes. Estella Leopold documented the palynoflora from the Kisinger Lakes site of the Aycross Formation in northwestern Wyoming and found 161 species in at least 41 families (MacGinitie, 1974). The dispersed palynoflora at Kisinger Lakes added 14 families to the overall diversity of the fossil flora. Many species represented in the dispersed palynoflora indicated warm temperate to moist tropical conditions (MacGinitie, 1974). The taxa usually restricted to cool temperate environments (e.g., Picea and Tsuga) were not abundant and were likely carried in from a higher elevation.

Within the species-rich Kisinger Lakes palynoflora, 23 monilophytes, 10 gymnosperms,

7 monocots, and 121 “dicots” were documented. At least 35 different species were observed in

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five (of 6) counts of 100 grains (MacGinitie, 1974). Lygodium spores (figured grain is ~89.4 µm in diameter, MacGinitie, 1974) were common, Pinaceae were rare in most samples, and “dicots” overall were dominant, but no single species was very numerous. The Kisinger Lakes flora seems to have a higher diversity of Pinaceae genera represented than is preserved at Blue Rim.

The widespread presences of Lygodium in the Kisinger Lakes microflora is also worth nothing as this is the most frequently encountered macrofossil in the lower horizon at Blue Rim.

Leopold also documented species of Carya (figured grain is ~29.6 µm in diameter) and Tilia

(MacGinitie, 1974), both of which are present at Blue Rim and are representative of moist, warm temperate conditions. However, it should be noted that Tilia-like pollen is also found in situ in other Eocene taxa including Florissantia (extinct) and extant Craigia (Manchester, 1992; Zetter et al., 2002). Other genera including Pinus, Salix (figured grain is ~21.1 µm in diameter),

Juglans, and Alnus are present at both Blue Rim and Kisinger Lakes (MacGinitie, 1974). Grains of Amaranthaceae (~31.0 µm in diameter) were also present at Kisinger Lakes (MacGinitie,

1974). In contrast, a large grain of Malvaceae (~63.4 µm in diameter) was preserved at Kisinger

Lakes (MacGinitie, 1974); the grains with an echinate ornamentation at Blue Rim are smaller and more aligned with pollen of Asteraceae. As with the Blue Rim dispersed pollen and spores, the Kisinger Lakes palynoflora is dominated by wind-pollinated taxa.

Leopold also compared the Kisinger Lakes palynoflora to multiple other Eocene pollen assemblages from Wyoming and noted six that were similar in taxonomic composition to

Kisinger Lakes. Two of these were in the same vicinity as the Kisinger Lakes flora, while one was in the Bridger Formation and another was from the Green River Formation (MacGinitie,

1974). Pollen with affinities to the genera of the Kisinger Lakes leaf flora that are also shared with the Blue Rim leaf flora include: Populus, Salix, and Serjania (MacGinitie, 1974).

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Green River Formation. Wodehouse (1932, 1933) was one of the first to document the pollen and spores of the Green River Formation. Recently, Nichols (2010) reviewed

Wodehouse’s original holotypes and accepted most of his generic assignments. Species of

Pinaceae include (holotype dimensions in parentheses): Pinus strobipites Wodehouse (corpus 48 by 45.5 µm, sacci 45 µm), Pinus scopulipites Wodehouse (corpus 56 by 40 µm, sacci 27 µm),

Pinus tuberculipites Wodehouse (corpus 53 by 64 µm, sacci 59 µm), Picea grandivescipites

Wodehouse (corpus 72 by 44 µm, sacci 45-48 µm), and Abies concoloripites Wodehouse (corpus

93.5 by 60 µm, sacci 63-72 µm) (Wodehouse, 1933; Nichols, 2010). Picea can be distinguished from Pinus by its larger size and smaller sacci in relation to the size of the grain; however, the size of Abies pollen overlaps with Picea making size a less reliable character to distinguish those two genera (Nichols, 2010). Pollen of Cupressaceae have also been recovered from the Green

River Formation (Wodehouse, 1933; Nichols, 2010); it is also present at Blue Rim. Wodehouse

(1933) recognized pollen of Ephedra in the Green River Formation and it is also present in unit

16 (UF 19297/2014 section) at Blue Rim. Nichols (2010) notes that the morphology of Ephedra pollen is distinctive, which makes it easy to confidently recognize in the fossil record.

Whereas pollen of Carya is present in the Green River Formation, represented by Carya viridifluminipites (Wodehouse) Wilson & Webster, that species ranges from 35-40 µm in diameter and does not form a circumpolar ring of thin exine. The lack of a circumpolar ring distinguishes the Green River Carya species from most of the grains observed at Blue Rim which do have a circumpolar ring (which is a feature of all extant species of the genus,

Whitehead, 1965). Alnus is represented in the Green River dispersed palynoflora by Alnus speciipites Wodehouse, ranging from 20-30 µm in diameter; Betula claripites Wodehouse is also present, usually with three annulate pores and approximately 25 µm in diameter (Wodehouse,

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1933; Nichols, 2010). Specimens with morphological similarities to the Green River taxa

Rhoipites bradleyi Wodehouse (tricolporate with long colpi), Malvaceae, and Salix are also present at Blue Rim (Wodehouse, 1933; Nichols, 2010). The Green River Malvaceae material is more similar to former “Bombacaceae” than to “Tiliaceae” or “Sterculiaceae” (Nichols, 2010).

Macginitie (1969) notes that Wodehouse’s pollen identifications may have been biased toward temperate species that were more easy to recognize with a more “moderate” number of species with tropical affinities. Macginitie (1969) also observed at least 24 genera from pollen obtained from a core collected from Colbran Road to the west of Rifle, CO. In that sample there were at least 4 types of legumes, Alnus, Betula, Platycarya, and many taxa that were also represented in the Green River Formation macroflora (MacGinitie, 1969)

Pollen of Fabaceae was common in sediment from both the Green River and Aycross

Formations (MacGinitie, 1969; MacGinitie, 1974). No grains with fabaceous affinities were identified from Blue Rim, but many grains remain unidentified.

Wasatch Formation. Nichols (1987) also reviewed the pollen from the Vermillion Creek coal bed of the Nilan Tongue of the Wasatch Formation (late Early Eocene, ~51 Ma). Platycarya platycaryoides (Juglandaceae) and Arecipites tenuiexinous (Arecaceae or Liliaceae s.l.) were dominant in that pollen assemblage; in total there were 8 species of pterophytes, 4 gymnosperms, and 39 angiosperms (Nichols, 1987). Eocene strata in the Denver Basin can also be recognized by the presence of Platycarya platycaryoides (Nichols and Fleming, 2002). Even though

Platycarya is restricted to Asia today, it was widespread (mostly pollen records) in the early and middle Eocene of North America (Leopold and MacGinitie, 1972). The taxonomic composition of the Wasatch palynoflora suggested a humid, subtropical climate that lacked frost.

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Nevertheless, the distinctive grains of Platycarya seem to be missing or very rare (see Fig. 3-

30M) from the Blue Rim assemblage, possibly reflecting an environmental difference.

In sum, the Blue Rim dispersed palynoflora includes taxa not otherwise present in the macroflora, likely representing species growing at higher elevations around the basin. Numerous species are shared with the similarly aged floras from northwestern Wyoming and the former

Green River lakes.

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Table 3-1. Summary of reproductive structures at Blue Rim. Taxon Family or Order Organ Horizon Quarries 15761, 15761N, 15761S, 19033, 19225, 19337, cf. Ampelopsis rooseae Vitaceae Fr., Sd. Lower 19338 Araceae Incertae sedis Araceae Fr. / Sd. Lower 18288 Beach Ball Type 1 Fr. or Sd.? Lower 15761S, 19337 Beach Ball Type 2 Fr. or Sd.? Lower 19225 cf. Calycites ardtunensis Fr. Upper 19296, 19297 cf. Cedrela sp. Meliaceae Fr. Upper 19297 Chaneya tenuis Rutaceae Fr. Upper 19296, 19297 Cluster Type 1 Fr. or Sd.? Lower 15761, 19225 Cluster Type 2 Fr. or Sd.? Lower 15761S, 19225, 19225N Cluster Type 3 Fr. or Sd.? Lower 15761N Cluster Type 4 Fr. or Sd.? Lower 15761N, 15761S, 19225N Cup-like flower w/tiny stamens Fl. Lower 15761N, 19225, 19337 Equisetum sp. Eq uisetaceae Strobilus/Tubers Both 15761, 19225, 19225N, 19297 Illigeria eocenia Hernandiaceae Fr. Upper 19296 Iodes/Biceratocarpum brownii Icacinaceae Fr. Lower 19225 15761, 15761N, 15761S, 18288, 19031, 19032, Iodes occidentalis Icacinaceae Fr. Lower 19225, 19337, 19338 cf. Keratospermum Araceae Fr. / Sd. Lower 19033, 19225, 19338 Lagokarpos lacustris Fr. Upper 19297 15761, 15761N, 15761S, 19032, 19225, 19225N, Landeenia aralioides Sapindales Fl., Fr., Sd. Both 19296, 19297, 19337, 19338, 19405 Large stamens Fl. Lower 15761, 19225, 19225N Larger Spike Fl. Lower 19225 Macginicarpa sp. Platanaceae Fr. Both 19296, 19297, 19337 Mini Spike Fr. or Fl. Lower 15761, 15761N Pentoperculum minimus Anacardiaceae Fr. Lower 15761, 15761N, 15761S, 19225, 19225N, 19337

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Table 3-1. Continued. Taxon Family or Order Organ Horizon Quarries Petals with central vein Fl. Lower 15761, 15761N, 15761S, 19225, 19337 Phoenix windmillis Arecaceae Fl. Both 15761, 15761N, 15761S, 19296 Poofball Fr. or Fl. Lower 15761, 15761N, 15761S, 19225, 19337, 19338 15761, 15761N, 15761S, 19031, 19032, 19225, Populus sp. 1 Salicaceae Fr. Lower 19225N, 19337, 19338 00341, 15761, 15761N, 15761S, 18288, 18289, Populus cinnamomoides Salicaceae Fr. Both 19031, 19032, 19225, 19225N, 19297, 19337, 19338 Pseudosalix Salicaceae Fr. Lower 15761N Spikey Sun Fr. or Sd.? Lower 19225N Sunburst (Homalieae) Salicaceae Fl. Lower 15761, 15761N, 15761S, 19337, 19338 Tiny 5-petal Fl. Lower 15761, 15761N, 15761S, 19225, 19337 Tiny winged Sd. Lower 15761N, 18288, 19225, 19225N, 19232, 19337 Three carpels Fr. Lower 19337 Two-sectioned crescents w/ tails Fr. or Sd.? Lower 19225N, 19337 Winged Teardrop Fr. or Sd.? Both 19225, 19297 Notes. Fl. = flower; Fr. = fruit; Sd. = seed

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Figure 3-1. Specimens of “Mini Spike.” A) UF 15761-22588’. B) Close-up of UF 15761- 22588’.C) Close-up of UF 15761-22588. D) UF 15761N-57442. E) UF 15761N- 57431. F) UF 15761N-57448’.

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Figure 3-2. Flowers assigned to “Sunburst.” These are representative of a new species in the tribe Homalieae of Salicaceae s.l. A) UF 15761-22658. B) Close-up of stamens of UF 15761-22658. C) UF 15761-22727. D) A different flower on the same hand sample, UF 15761-22727. E) UF 15761-30993. F) Close-up of stamens of UF 15761-30993. G) UF 15761-22606 with drop of nail polish showing site where in situ pollen was extracted from anther. H) UF 15761-22728 with well-defined nectaries. I) UF 15761- 22721’. J) UF 15761-22718’. K) UF 15761-48507. L) A specimen from Kisinger Lakes, UF 19374-60361. M) Another specimen from Kisinger Lakes, UF 19377- 61625’. Scale bars = 2 mm, except B = 1 mm.

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Figure 3-3. In situ pollen extracted from the anthers of the “Sunburst” flower morphotype. The pollen features match those of Salicaceae s.l. A-E) Pollen viewed via SEM, UF 15761-22606. F & G) Pollen viewed via LM, UF 15761-22721. Scale bars = 10 µm.

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Figure 3-4. Fossils assigned to the “Poofball” morphotype. A) UF 15761-22856. B) UF 15761- 22580. C) UF 15761N-44000. D) UF 15761N-61366. E) UF 15761N-57678. F) UF 15761N-57784. G) UF 15761N-57691. H) UF 15761-22587. I) UF 15761-22582. Scale bars: E & F = 2 mm, all others = 5 mm.

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Figure 3-5. In situ pollen viewed via SEM from UF 15761-22856 (see Fig. 3-4A). A) Scale bar = 20 µm. B) Scale bar = 8.57 µm. C) Scale bar = 3.33 µm. D) Scale bar = 5.00 µm. E) Scale bar = 8.57 µm.

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Figure 3-6. In situ pollen viewed by SEM of UF 15761N-57784 (see Fig. 3-4F). A) Scale bar = 10 µm. B) Scale bar = 2 µm. C) Scale bar = 3 µm. D) Scale bar = 10 µm. E) Scale bar = 20 µm. F) Scale bar = 5 µm.

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Figure 3-7. Flowers assigned to “Tiny 5-petal.” A) UF 15761N-57769’. B) UF 15761N-57740. C) UF 15761N-57754. D) UF 19225-57054. E) UF 15761S-57915. F) UF 15761N- 57769. G) UF 15761N-57773. H) UF 15761N-57723. Scale bars = 2 mm, except F = 5 mm.

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Figure 3-8. Flowers assigned to “Cup-like flower with tiny stamens.” A) UF 19337-61553’. B) UF 19337-61553. C) UF 19225-54549. D) UF 15761N-43971. E) UF 19225-57029’. F) UF 19337-58001. G) UF 15761N-57744. Scale bars = 5 mm.

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Figure 3-9. Flowers assigned to “Petals with central vein.” A) UF 19225-57037. B) UF 15761N- 57298. C) UF 19337-61549. D) UF 15761N-57340. E) UF 15761N-57333. F) UF 19337-57997. G) UF 15761S-57910. H) UF 19225-57080’. I) UF 19225-54573. Scale bars = 5 mm.

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Figure 3-10. “Large stamens” and Landeenia aralioides (MacGinitie) Manchester and Hermsen. A) UF 19225-52024. B) UF 19225-57003. C) UF 19337-58070. D) UF 19297- 43673’. E) UF 19337-57981. F) UF 19337-57982. G) UF 19337-61586. Scale bars = 5 mm.

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Figure 3-11. Selection of fruits from Blue Rim. A) Illigera eocenia Manchester and O’Leary, UF 19296-43961. B-E) Chaneya tenuis (Lesquereux) Wang and Manchester. B) UF 19297-54351. C) UF 19296-43815. D) UF 19296-43815’. E) UF 19297-54351’. F & G) cf. Cedrela. F) UF 19297-43915. G) UF 19297-43915’. H-K) Pentoperculum minimus (Reid and Chandler) Manchester. H) UF 15761N-57290. I & J) UF 15761N- 57286 (2 specimens on same hand sample). K) UF 15761N-57287. Scale bars = 5 mm.

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Figure 3-12. Fruits of Macginicarpa sp. (Platanaceae). A) UF 19296-43814. B) UF 19296- 43814’. C) UF 19296-54628. D) UF 19296-43858’. E) UF 19296-54629. Scale bars = 5 mm.

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Figure 3-13. Fruits and seeds of cf. Ampelopsis rooseae (Vitaceae). A) UF 15761S-57814. B) UF 15761-30946. C) UF 15761S-57830. D) UF 19337-57996. E) UF 15761-48506. F) UF 15761N-57345. Scale bars = 5 mm.

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Figure 3-14. Fruits of Populus sp. 1 (A-C) and Populus cinnamomoides (Lesquereux) MacGinitie (D-H). A) UF 15761N-61397. B) UF 19337-57990. C) UF 15761S- 57810’. D) UF 15761N-57581’. E) UF 15761N-61476. F) UF 19337-58085. G) UF 19337-57989’. H) UF 19337-58000. Scale bars = 5 mm.

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Figure 3-15. Specimens assigned to cf. Keratospermum (A & B), Araceae (C), Lagokarpos lacustris McMurran et Manchester (D & E). A) UF 19225-54576. B) UF 19033- 39030. C) UF 18288-58209. D) UF 19297-54243. E) UF 19297-58134. Scale bars A & B = 10 mm; scale bars C-E = 5 mm.

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Figure 3-16. Specimens assigned to Cluster Type 1 (A-E) and Araceae (F-H). A) UF 15761- 53543. B) Close-up of UF 15761-53543. C) UF 19225-57085. D) UF 19225-57083’. E) UF 19225-57072. F) UF 18288-58202. G) UF 18288-58202’. H) UF 18288-58213. Scale bar = 5 mm.

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Figure 3-17. Specimens assigned to “Winged Teardrop” (A-C), Beach Ball Type 1 (D & E), Beach Ball Type 2 (F), and “Tiny Winged” (G-I). A) UF 19225-57123. B) UF 19297- 58137’. C) UF 19297-43753. D) UF 15761S-57818. E) UF 19337-61552’. F) UF 19225-56345. G) UF 15761N-61425. H) UF 19337-61581. I) UF 19225N-61803. Scale bars = 5 mm.

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Figure 3-18. Specimens assigned to cf. Calycites ardtunensis (A & B), “Three carpels” (C), “Two Sectioned Crescents with Tails” (D-G), and “Spikey Sun” (H & I). A) UF 19296-43856. B) UF 19296-43857. C) UF 19337-61522’. D) UF 19337-61579. E) UF 19337-69229. F) UF 19337-69228’. G) UF 19337-61520’. H) UF 19225N-57943. I) UF 19225N-61816. Scale bars = 5 mm.

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Figure 3-19. Specimens of Cluster Type 2 (A-C), Cluster Type 3 (D), and Cluster Type 4 (E-G). A) UF 15761S-57878’. B) UF 15761S-57899. C) UF 15761S-57900. D) UF 15761N- 43956. E) UF 15761N-61380’. F) UF 15761S-61514’ G) UF 19225N-61824. Scale bars = 5 mm.

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Figure 3-20. Specimens of Larger Spike (A & B) and Equisetum sp. (C-G). A) UF 19225- 57041’. B) UF 19225-57041. C) UF 19225N-57945. D) UF 19225N-61802. E) UF 19225N-61827. F) UF 19225N-69006. G) UF 19225N-57935. Scale bars = 5 mm.

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Figure 3-21. In situ pollen from specimen UF 19225-57041 (A-C) and CT Scan images of a few reproductive structures at Blue Rim (D-I). A-C) In situ tricolpate pollen from UF 19225-57041 (See Figs. 3-20 A & B). Scale bars = 10 µm. D) CT Scan of “Mini Spike” specimen UF 15761N-57438. Arrow is pointing to flower showing 4-5 stigmas. For scale, each individual flower is ~1 mm in diameter. E) Flower of “Sunburst,” UF 15761-22721 (See counterpart in Fig. 3-2I). Arrow is indicating one of the eight 3-D nectary pads at the base of each tepal. For scale, each nectary is ~1 mm long. The central area of sediment is ~1.5 mm across and the tepal on the lower right is just over 6 mm long. F) Underside of “Three carpels” showing pedicel and median keel on each carpel, UF 19337-61522’ (See Fig. 3-18C). For scale, each carpel is ~3-3.5 mm by ~2-2.5 mm. G) Specimen UF 15761N-43956 (see Fig. 3-19D) showing numerous rounded seeds. For scale, cluster is ~12 mm across by ~20 mm long; individual seeds are 1-2 mm in diameter. H) Specimen of “Winged Teardrop,” UF 19225-57123’, counterpart in Fig. 3-17A. For scale, central seed body is ~5.5 mm long by 3 mm wide. I) Specimen UF 19225-57072 (see Fig. 3-16E). For scale, each barrel-shaped seed is ~1-1.25 mm long by ~0.75 mm wide.

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Figure 3-22. Dispersed spores and pollen from UF 19404. A) Monolete spore, cf. Laevigatosporites haardtii (see Frederiksen, 1980). B-G) Trilete spores. H) cf. Lygodium. I) Pinaceae. J) Likely ornamented spore. K) Large trilete spore. L) Elongate palynomorph. M & N) Pinaceae. Photos by William Paxton. Scale bar (lower left) = 20 µm for images A-F, I. Scale bar (lower right) = 20 µm for images G, H, J-N.

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Figure 3-23. Dispersed pollen from UF 19404. A) Triporate grain, cf. Carya. B) Slightly ~verrucate, oval grain with 4 pores, cf. Ulmaceae. C & D) cf. Tilia. E) Pentaporate grain with arci, Alnus sp. F) Polyporate grain, cf. Pterocarya, Juglandaceae. G) Small, sculptured, tricolpate grain. H) Porate grain with echinate ornamentation. I) Likely tricolpate. J) Tricolpate grain. K) cf. Platanus. L) Large tricolporate grain. M) cf. Betula N) Triporate grain. Photos by William Paxton. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-24. Dispersed pollen from unit 8 of the 2012/UF 19225 stratigraphic section. A) Triporate pollen, cf. Carya. B) Elongated monosulcate grain. C) Ornamented tricolpate grain. D) Large echinate ornamentation, cf. Asteraceae. E) Polyporate, cf. Chenopodium. F) Polyporate, cf. Juglans. G) Polyporate, cf. Chenopodium. H) Tricolpate grain. I-N) Bisaccate pollen, Pinaceae. Photos by William Paxton. Scale bar (lower left) = 20 µm for images A-H. Scale bar (lower right) = 20 µm for images I-N.

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Figure 3-25. Dispersed spores and pollen from unit 18 of the 2012/UF 19225 stratigraphic section. A-G) Trilete spores, B) cf. Lygodium. C-D) cf. Granulatisporites/Deltoidispora. H) cf. Ephedra. I) cf. Cicatricosisporites dorogensis (see Frederiksen, 1980). J) Unidentified, likely spore. K) cf. Picea. L & M) cf. Pinus. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-26. Dispersed pollen from unit 18 of the 2012/UF 19225 stratigraphic section. A-E) Monosulcate, likely monocot grains. F-H) Monosulcate clusters. I & J) cf. Carya. K) Polyporate grain. L) cf. Alnus. M) cf. Iodes. N) Striated tricolpate, cf. Acer. O-U) Tiny, reticulate tricolpate, cf. Salix. V) cf. Corylus (but common morphology). W) cf. Betulaceae X & Y) 4-pores, cf. Ulmaceae. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-27. Dispersed spores from unit 11 of the 2014/UF 19297 stratigraphic section. A) Monolete spore, B) Monolete spore, cf. Laevigatosporites haardtii (see Frederiksen, 1980). C-K) Trilete spores. Photos by Alyssa Zakala. Scale bar (lower left) = 20 µm for images A-F. Scale bar (lower right) = 20 µm for images G-K.

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Figure 3-28. Dispersed pollen from unit 11 of the 2014/UF 19297 stratigraphic section. A & B) cf. Carya. C) cf. Juglandaceae. D) Small monosulcate. E) Triporate, cf. Betulaceae. F) Unidentified grains. G) Likely monosulcate. H) Large tricolporate. I) Unidentified tetrad. Photos by Alyssa Zakala. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-29. Spores and gymnosperm pollen from unit 15 of the 2014/UF 19297 stratigraphic section. A) Monolete spore. B-D) Trilete spores. E) Likely spore. F-H) Cupressaceae s.l.. I-M) Pinaceae. Photos by Morgan Pinkerton. Scale bar (lower left) = 20 µm for all images except L. Scale bar in L = 20 µm (image taken at 100x instead of 200x).

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Figure 3-30. Pollen from unit 15 of the 2014/UF 19297 stratigraphic section. A & B) Alnus (Betulaceae). C) cf. Juglandaceae. D) cf. Malvaceae s.l.. E & F) cf. Carya (Juglandaceae). G) Round ornamented grain. H) Oblong sculpted grain. I) cf. Sapindaceae or Rosaceae. J) cf. Ilex (Aquifoliaceae). K) cf. Juglandaceae. L) cf. Magnoliaceae. M) cf. Platycarya (Juglandaceae). N) Ornamented tricolpate. O) Small grain. P) cf. Malvaceae s.l.. Q) Ornamented grain with large colpus. Photos by Morgan Pinkerton. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-31. Pollen from unit 15 of the 2014/UF 19297 stratigraphic section. A-D) Tricolpate. E) Parasyncolpate grain. F-G) Porate grains. H) Rounded grain with likely narrow colpi. I) cf. Artemisia (Asteraceae). J) Pursed triporate, cf. Betulaceae. K) Likely pentaporate grain. L & M) cf. Ulmus (Ulmaceae). N) Large tricolporate grain. Photos by Morgan Pinkerton. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-32. Pollen from unit 15 of the 2014/UF 19297 stratigraphic section. A-C) Pursed triporate grains, cf. Betulaceae. D) Porate grain with small spines. E) cf. Malvaceae s.l.. F) cf. Juglandaceae. G) Grain with thickened colpi margins. H) cf. Malvaceae s.l.. I) Triporate. J) Porate grain. K) cf. Ulmaceae. L) Tricolpate grain. Photos by Morgan Pinkerton. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-33. Spores and gymnosperm pollen from unit 16 of the 2014/UF 19297 stratigraphic section. A & B) Trilete spores. C & D) cf. Cupressaceae s.l.. E-G) Ephedra. H & I) Pinus (Pinaceae). J) Likely spore. K-O) Pinus (Pinaceae). Photos by Morgan Pinkerton. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-34. Pollen from unit 16 of the 2014/UF 19297 stratigraphic section. A & B) cf. Alnus (Betulaceae).C) cf. Betulaceae. D) cf. Juglans nigra (Juglandaceae). E & F) cf. Carya (Juglandaceae). G) cf. Fagaceae (and others). H) cf. Tilia (Malvaceae). I & J) cf. Celtidoideae (Ulmaceae). K) cf. Emilia (Asteraceae). L-N) cf. Asteroideae (Asteraceae). O) cf. ?Ranunculaceae. P) cf. ?Fagaceae. Q & R) cf. ?Ranunculaceae. S & T) cf. ?Sapindaceae. Photos by Morgan Pinkerton. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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Figure 3-35. Pollen from unit 16 of the 2014/UF 19297 stratigraphic section. A & B) cf. Chenopodium. C) cf. Juglans. D) Unidentified pollen grain. E) Tricolpate, cf. ?Fagaceae. F) Tricolpate, cf. ?Sapindaceae or ?Myrtaceae. G) Unidentified palynomorph. H-J) Tricolpate grains. K-O) Tricolporate, cf. ?Fagaceae. Photos by Morgan Pinkerton. Scale bar = 20 µm. All pictures at the same magnification, so figured size is proportional to actual size.

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CHAPTER 4 FOSSIL PALM FLOWERS FROM THE EOCENE OF THE ROCKY MOUNTAIN REGION WITH AFFINITIES TO PHOENIX L. (ARECACEAE: CORYPHOIDEAE)1

Among monocots, palms have the richest fossil record, with widespread occurrences encompassing all plant organs (Harley and Baker, 2001; Harley, 2006; Pan et al., 2006;

Dransfield et al., 2008). They have been documented from localities around the world with credible records from the Late Cretaceous to the present [there are questionable records from the

Early Cretaceous (Harley, 2006)]. However, most prior records are based on leaves, stems, seeds, and pollen; floral remains have been elusive. Today, there are more than 2,000 species of palms in 183 genera of the tropics and subtropics (Hahn, 2002; Couvreur et al., 2011). Because their physiology precludes survival in areas with extremely cold winters, palm fossils can also be used to provide evidence of past climates (Wing and Greenwood, 1993; Harley, 2006).

A new species of Phoenix L. (Coryphoideae, Arecaceae) is described based on impression and compression fossil flowers found in Eocene strata throughout the Rocky

Mountain region. Well-preserved flowers are rare in the Cenozoic fossil record and the occurrence of the same kind of flower at multiple localities is particularly unusual. The fossil staminate trimerous flowers presented here occur in the highest concentrations in the lacustrine

Green River and fluvial Bridger Formations of southwestern Wyoming. They are also preserved, in lower abundance, in Green River strata in northwestern Colorado and northeastern Utah. One specimen was also recovered from the Wind River Formation of central Wyoming (Fig. 4-1).

The Blue Rim flora of the Bridger Formation (~49.5 Ma) in southwestern Wyoming preserves the majority of these fossil flowers, as well as at least eight other types of flowers along with

1Reprinted with permission from: ALLEN, S.E. 2015. Fossil Palm Flowers from the Eocene of the Rocky Mountain Region with Affinities to Phoenix L. (Arecaceae: Coryphoideae). International Journal of Plant Sciences 176: 586- 596. © 2015 by The University of Chicago.

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fossilized leaves, wood, and other reproductive organs. The fossil material is compared with other fossil and extant palm flowers to justify its placement in Phoenix. A review of previously documented phoenicoid fossils is presented and the biogeographic and paleoclimate implications of this taxonomic assignment are discussed.

Material, Methods, and Geologic Setting

Material

Most of the specimens examined are from the Blue Rim flora of the Bridger Formation

(UF localities 15761, 15761N, 15761S, and 19296) in southwestern Wyoming (Figs. 4-2A-D). A single specimen has been recovered from the Wind River Formation to the northeast of Riverton,

WY (in northeastern Fremont County, DMNH locality 5102, Fig. 4-2E). Specimens from several members of the Green River Formation have been found at multiple localities including: the

Parachute Creek Member [Watson, UT (Fig. 4-2F, UCMP locality PB02016), Rio Blanco

County, CO (Figs. 4-2G&H, UF locality 00579, USNM/USGS locality 8643, 8644), Garfield

County, CO (USNM locality 41140)], the Laney Member [Barrel Springs, WY (Figs. 4-2I-K),

UF localities 18150 and 18151], and the Fossil Butte Member [Blue Moon Fish Quarry (Fig. 4-

3A, UF locality 00319), Kemmerer, WY (Fig. 4-3B), and Fossil Butte National Monument,

WY]. In addition to the specimens we collected and deposited at the Florida Museum of Natural

History, Gainesville, Florida (prefixed UF); additional specimens from the US National

Museum, Washington, D.C. (USNM), Denver Museum of Nature and Science (DMNH), Fossil

Butte National Monument (FOBU), University of California Museum of Paleontology, Berkeley

(UCMP), Field Museum of Natural History, Chicago (FMNH), and the Utah Museum of Natural

History, Salt Lake City (UMNH) were examined.

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Methods

Macrofossils. Specimens were collected in the field by splitting siltstones and shales.

Measurements were calculated using ImageJ (http://imagej.nih.gov/ij/; Rasband, 1997-onwards) after specimens were photographed. Petal length was measured from the central circular disk of the flower to the tip. Sepal length was measured from the very center of the flower to the tip.

Petal and anther width were measured in the middle third. The macrofossils were compared to herbarium specimens (more information below). Photographs were taken with either a Pentax K-

7 or a Nikon D300 digital camera. Helicon Focus (photo stacking software) was used in some cases and all photos received minor adjustments in Adobe Photoshop.

In situ pollen. One specimen (UF18150-56374, Fig. 4-2K) from the Barrel Springs I site of the Green River Formation, with particularly well preserved pollen sacs, was investigated for in situ pollen morphology. The specimen was observed and photographed using epifluorescence microscopy to assess the potential for in situ pollen recovery (Figs. 4-4A&B). Anther material was removed with a needle and treated with 10% KOH for 2 to 5 minutes. The grains were observed (in a 50/50 mixture of H2O and glycerol) and photographed by light microscopy on a

Nikon Eclipse E600 microscope with a Pentax K-7 camera or a Canon SLR EOS Rebel XSI camera with EOS Utility (Figs. 4-4C-E). Some pieces of anther material were further treated with 49% HF for 2 hours to remove debris and washed in H2O before being transferred onto a

SEM stub for higher resolution viewing. SEM images were taken in the University of Florida’s

Department of Molecular Genetics and Microbiology (Figs. 4-4F-K). Pollen grain images from both the light microscopy and SEM were measured using ImageJ.

Extant comparative material. Images were obtained of herbarium material [Phoenix cf. canariensis Chabaud specimens 213195 and 213196 at the University of Florida Herbarium

(FLAS). Collected in August 2004 in Kanapaha Botanical Gardens, Gainesville, FL by S. Barry

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Davis #1158] using a Pentax K-7 camera (Figs. 4-5A-C). Images of extant pollen (Phoenix reclinata Jacq., MO 2094073, Ghana and Phoenix dactylifera L., BH Bailey and Bailey, CA,

USA) were taken with the same equipment mentioned above (Figs. 4-5D-F).

Geologic Setting

Specimens assigned to the new species are from the Blue Rim escarpment of the Bridger

Formation in southwestern, Wyoming, the Wind River Formation in central Wyoming, and the

Green River Formation at various sites in southwestern Wyoming, northeastern Utah, and northwestern Colorado. The Blue Rim flora is in lower Bridger strata (Kistner, 1973; Allen,

2011) and is estimated to be 49.5 Ma. This escarpment preserves interbedded lacustrine and fluvial units. The majority of the Blue Rim fossils were collected from a single quarry (UF

15761N).

The Green River Formation has been well studied (e.g., Bradley, 1973; Eugster and

Hardie, 1975; Sullivan, 1980; Roehler, 1992a) and records large interior lakes spanning sections of Wyoming, Colorado, and Utah from ~53.5 to 48.5 Ma (Smith et al., 2003; Smith et al., 2008).

The fossil Phoenix flowers have been found in strata throughout the Green River Formation including the Fossil Butte, Parachute Creek, and Laney Members. The Fossil Butte Member of the Green River Formation in Fossil Basin (southwestern Wyoming) is estimated to be 51.66 ±

0.17 Ma based on sanidine from the K-spar tuff (Smith et al., 2008). The Parachute Creek

Member of the Green River Formation in the Piceance Creek Basin of Colorado ranges from ~51 to 48.5 Ma (Smith et al., 2008). The Laney Member of the Green River Formation was deposited from ~49.5 to 48.7 Ma (Smith et al., 2008). The flowers from Barrel Springs in the Washakie

Basin, near Wamsutter, WY were preserved in the Laney Member of the Green River Formation.

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The Wind River Formation is early Eocene (Bridgerian NALMA, Krishtalka et al., 1987) in age and is located in the Wind River Basin of central Wyoming (Soister, 1968). The single specimen was recovered from a site east of Shoshone in northeastern Fremont County.

Systematics and Results

Order—Arecales Bromhead (1840).

Family—Arecaceae Bercht. & J.Presl (1820).

Genus—Phoenix L.

Species—Phoenix windmillis S.E. Allen sp. nov.

Diagnosis—Flowers actinomorphic, 6.6 to 9 mm in diameter; perianth differentiated into three small distinct triangular sepals (0.8 to 2.1 mm long) in the outer whorl and three distinct elliptical petals (2.8 to 6.1 mm long) in the inner whorl; androecium of six large elongate stamens; in situ pollen monosulcate, globose to boat shaped (20.9 to 39.1 µm, avg. 27.6 µm) with a finely reticulate exine.

Holotype, hic designatus—UF 18150-56374 (Fig. 4-2K).

Repository—Florida Museum of Natural History (FLMNH); Gainesville, FL 32611.

Type Locality—Barrel Springs I, near Wamsutter, Sweetwater County, Wyoming.

Stratigraphic position and age—Laney Member, Green River Formation, latest Early Eocene.

Paratypes—UF 15761N-57347, UF 15761N-57363, UF 15761N-57365, UF 18150-56377,

UCMP 391008.

Etymology—The specific epithet windmillis refers to this taxon’s field name of “Windmill” as the three petals are oriented just like the blades of a modern wind turbine.

Additional Specimens Examined—Blue Rim, WY (Bridger Formation): UF 15761-22608 to

22610, 30963; UF 15761N-43969, 43970, 43972, 49318, 57296, 57346, 57349, 57350, 57351,

57352, 57354, 57355, 57356, 57357, 57359, 57360, 57361, 57362, 57364, 57366, 57367, 57368,

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57369, 57370, 57371, 57372, 57374, 57375, 57768, 58644, 62020, 61367, 61368; UF 15761S-

57921; UF 19296-43803; Barrel Springs I & II, WY (Laney Member, Green River Formation):

UF 18150-56375, 56378, 56379; UF 18151-56376, 56380; Rio Blanco and Garfield Counties,

CO (Parachute Creek Member, Green River Formation): UF 00579-60660, USNM 608674

(USGS loc. 8643), USNM 608675 (USGS loc. 8644), USNM 5821071 (USNM loc. 41140);

Fossil Lake Area, WY (Fossil Butte Member, Green River Formation): FMNH PP43972,

PP55104; FOBU 847, 848, 9982, 9983, 10706, 10727, 13300; UF 00319-56780, 56781, 59522,

UMNH PB 118; Wind River Formation, WY: DMNH EPI.32900 (DMNH loc. 5102).

Description—

Macrofossils. Phoenix windmillis flowers are small and range from 6.6 to 9 mm in diameter. The perianth is differentiated into two whorls, with three small distinct triangular sepals in the outer whorl and three distinct elliptical petals in the inner. Sepals are often not visible (may be hidden by a thin layer of sediment; they are more commonly visible in the highly compressed shale specimens) or preserved, but range from 0.8 to 2.1 mm when present with an average of 1.4 mm. Petals range from 2.8 to 6.1 mm long with an average length of 4.1 mm.

Petal width ranges from 1.2 to 3.0 mm with an average of 2.1 mm. No gynoecia were observed.

The androecium consists of six large stamens without (visible) filaments. When present, the elongate anthers range in size from 3.4 to 6.3 mm long, averaging 4.5 mm. Anther width varies from 0.6 to 1.0 mm with an average of 0.7 mm (Figs. 4-2A-K & 4-3A-B).

In situ pollen. Pollen extracted directly from the anthers varies from globose to boat- shaped (Figs. 4-4B-J) with a finely reticulate exine. Grains monosulcate with the longitudinal aperture ~75–85% the length of the whole grain. The lumina are variable in shape and the

1 Note that this specimen was listed as 79089 in the original publication. However, this is a primary collection number and the correct USNM number is 582107.

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surrounding muri are smooth (Fig. 4-4K). Pollen grains measured from the light microscopy images averaged 32.2 µm at the widest point (range 26.7 to 39.1 µm). Grains measured using the

SEM images averaged 24.2 µm along the long axis (range 20.9 to 28.9 µm). The combined average was 27.6 µm from 19 measurements. The larger size from the light microscopy grains may be due to it being mounted in 50% glycerol, which is known to cause pollen grains to swell

(Faegri et al., 1989; Moore et al., 1991).

Discussion

Specimens studied from the early Eocene Fossil Butte Member of the Green River

Formation tend to be slightly larger than those from other localities (the Wind River specimen was excluded because the petals were not complete). Petal length ranges from 3.6 to 7.1 mm

(mean = 5.08 mm, SD = 1.28, n = 15 measurements from five specimens. Petal width ranges from 1.2 to 2.1 mm (mean = 1.59 mm, SD = 0.29, n = 14 measurements from five specimens). In contrast, the specimens preserved at Blue Rim, Barrel Springs, and the Parachute Creek Member of the Green River Formation are typically smaller, with petals ranging from 2.8 to 5.9 mm long

(mean = 4.0 mm, SD = 0.66, n = 100 measurements from 43 specimens). However, the petals from these localities are wider than those from Fossil Butte ranging from 1.3 to 3.0 mm (mean =

2.13 mm, SD = 0.37, n = 104 measurements from 44 specimens). There are fewer specimens and measurements from Fossil Lake as compared to the other localities; nevertheless the differences are statistically significant. Using a two-tailed T-test with unequal variances there is a significant difference between the length and width of the petals between the Fossil Lake specimens and the other localities (Length: tstat = 3.23, tcrit = 2.13; Width: tstat = -6.33, tcrit = 2.09). Morphologically, the flowers seem to coincide in every other detail, however (although pollen was not extracted from the Fossil Butte specimens). Whether these differences indicate different species, or perhaps adaptation of the same species to different environmental conditions is not certain, but in

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the absence of pronounced morphological differences, it seems reasonable to treat them collectively as one taxon.

Systematic Considerations

Numerous angiosperm families, especially within the monocots, are trimerous. As more dicotyledonous leaf taxa are preserved in the localities with Phoenix windmillis, the possible systematic affinities within the Magnoliid and Eudicot clades were reviewed. Within the

Magnoliales, Magnoliaceae, Annonaceae, and Myristicaceae frequently have trimerous perianth, but they typically have numerous stamens, unlike Phoenix windmillis. Furthermore,

Magnoliaceae and Annonaceae usually have bisexual flowers, whereas the fossils are staminate only. Lauraceae are characterized by six perianth parts, but these are rarely differentiated into sepals and petals. In addition, Lauraceae pollen is nonapeturate, spiny rather than reticulate, and is very delicate and rarely preserved in the fossil record. While Aristolochiaceae tend to have trimerous perianth, the petals are usually not present except in Saruma Oliv. where they are broad, unlike the petals of Phoenix windmillis.

Trimery can also be found in the basal eudicots including the Ranunculales; however the presence of tricolpate pollen in most eudicot families makes this unlikely. Menispermaceae flowers are trimerous and unisexual, but most often have six sepals and petals. Berberidaceae are also frequently trimerous, but six sepals and twelve petals (in two whorls) is the most common condition.

The differentiation of perianth into separate sepals and petals is rare in the monocots. The most common condition is six undifferentiated tepals, in two whorls (Remizowa et al., 2010).

Some genera of the Liliaceae, including Calochortus Pursh. and Scoliopus Torrey (Utech, 1992), have a differentiated trimerous perianth, but they only have three stamens, rather than six as seen in the fossil specimens. Additionally, the petal and stamen shapes do not correspond to P.

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windmillis. Both of these genera are herbaceous which makes them less likely to fossilize. Two whorls of perianth are also found in the petaloid core of the Alismatales, and the commelinid clade including Commelinaceae, Arecales, and some families of the Poales (including

Mayacaceae, Rapateaceae, and Xyridaceae; Remizowa et al., 2012). For example, Alisma triviale

Pursh. (Alismataceae) has differentiated perianth and the number of parts in the calyx, corolla, and androecium correspond to the fossil taxon (Singh and Sattle, 1972), but the overall shape and morphology of the petals and stamens do not correspond with the fossil specimens. In addition, the pollen of Alismataceae are typically two to polyporate. Many genera of Arecaceae have morphological similarities to Phoenix windmillis; however the combination of characters in the macrofossils and in situ pollen are most closely aligned with extant Phoenix.

Phoenix, known as the date palms, is the only genus in the monophyletic Tribe

Phoeniceae (J.Presl, Wšobecný Rostl.) which is one of three tribes in the Coryphoideae subfamily of the Arecaceae (Dransfield et al., 1990). The Coryphoideae are sister to all other palm clades except Calamoideae and Nypa Steck and have the highest concentration of unspecialized character states across the palm family (Dransfield et al., 1990; Asmussen et al.,

2006).

The ~13-17 species of Phoenix are most easily distinguished by their leaf and leaflet morphology (DeMason et al., 1982). The leaves are pinnate and induplicate, while the rest of the

Coryphoideae palms have palmate or costapalmate leaves (Dransfield et al., 1990; Barrow, 1998;

Dransfield et al., 2008). Interestingly, no pinnate, induplicate fronds have been recovered at any of the localities with Phoenix windmillis. This is either a taphonomic artifact or suggestive of how rarely palms shed their fronds (Burnham, 1989; Gastaldo, 1992; Gastaldo and Huc, 1992;

Burnham, 1994b). Phoenix leaflets do not have a true midrib; the center of the leaflet has

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expanded cells with scattered vascular bundles and fibers (Barrow, 1998). Hence it is possible that isolated leaflets, if present, might be dismissed as representing other monocot remains.

Staminate flowers of modern Phoenix have two alternate whorls of perianth parts composed of three connate sepals and three valvate petals that are much larger than the calyx.

This genus usually has six stamens with short, erect filaments in two whorls opposite the perianth (DeMason et al., 1982; Barrow, 1998; Dransfield et al., 2008). In modern Phoenix canariensis, the stamens are sessile, basifixed, and adnate to the petals (Prigge and Gibson,

2012). No filaments were observed in the fossil material; suggesting they were quite short.

While the details of the filaments are not preserved in Phoenix windmillis, the morphology of extant Phoenix flowers is in agreement with the other characters preserved in the fossils. Phoenix is dioecious, but immature staminate and pistillate flowers cannot be morphologically distinguished and their development is very similar (DeMason et al., 1982; Barrow, 1998). The male and female flowers of Phoenix dactylifera only diverge morphologically when the stamens elongate and become bilobed in the staminate flowers (DeMason et al., 1982).

All species of Phoenix have elliptical, monosulcate pollen which varies from symmetrical to slightly asymmetrical (Tisserat and DeMason, 1982; Barrow, 1998). Phoenix has some of the smallest pollen grains of the coryphoid palms (Ferguson and Harley, 1993). The size of Phoenix pollen varies from 16-30 µm in polar diameter and 9-15 µm in equatorial diameter (Kedves,

1980; Tisserat and DeMason, 1982; Barrow, 1998). These sizes are similar to the pollen of

Phoenix windmillis. Grains are tectate with a finely reticulate exine (Tisserat and DeMason,

1982; Ferguson and Harley, 1993; Barrow, 1998). In the exine, the lumina are smaller than the muri between them (Tisserat and DeMason, 1982). The lumina diameter can be up to 0.5 µm

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(Kedves, 1980). Kedves (1980) noted that Phoenix has very uniform pollen morphology among species and is therefore of limited utility for species-level identification.

Simple, monosulcate, tectate pollen with an unsculptured or finely sculptured exine is very common across the palms (Harley, 1990), so the pollen morphology of isolated fossil grains could not be assigned exclusively to Phoenix. However, the pollen characters in combination with the floral morphology permit assignment of the fossils to this genus.

Biogeography

Phoenix is one of the most widely distributed genera in the Arecaceae. It is native to the

Old World with a range from the Canary Islands through Africa, the southern Mediterranean,

Arabian Peninsula, India, and southeast Asia (Barrow, 1998; Dransfield et al., 2008). Phoenix has also been introduced to the New World and is the oldest-known cultivated tree (Tisserat and

DeMason, 1982). Berry (1914) noted that specimens assigned to Phoenix dactylifera fossilis were found in Pliocene and Pleistocene sediments of southern Europe, suggesting Phoenix was native to these areas until very recently. Fossils assigned to this genus extend back to the Eocene in mainland Europe and North America (as reviewed in “Fossil Record of Phoenix”).

Species of Phoenix grow in a wide range of habitats from sea level to 2000 meters in elevation (Barrow, 1998). However, despite its ability to occupy habitats ranging from the understory of a pine forest to a mangrove ecosystem, Phoenix requires constant root moisture.

Therefore it can be used as an indicator of water, seasonal swamps, or floods in dry areas

(Barrow, 1998).

The presence of Phoenix in central North America in the Eocene greatly expands the geographic range of this genus in the past. Other fossils have been assigned to Phoenix from localities outside its current range (e.g., Europe) as documented in “Fossil Record of Phoenix.”

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In addition, the Blue Rim flora in southwestern Wyoming preserves other taxa restricted to the old world today, including Iodes Blume (Icacinaceae, S.E. Allen, personal observation).

Fossil Record of Phoenix

Palms have been reported from the fossil record from the Early (dating and/or taxonomic assignment questionable) to early Late Cretaceous. It is suggested that extant palm lineages began diversifying at northern latitudes (Laurasia) approximately 100 Myr; the crown clade

Coryphoideae is estimated to be 66 Ma (Couvreur et al., 2011). The fossil record of Arecaceae has been extensively reviewed elsewhere (e.g., Harley, 2006; Dransfield et al., 2008), so only the records of the Tribe Phoeniceae are discussed here.

Stems. Palm wood assigned to Phoenix has been found in Africa (Pan et al., 2006).

Dechamps (1987; Dechamps and Maes, 1987) documented silicified fossil wood from the early

Pliocene Sahabi Formation in northern Africa (Libya). The stem fragment reported as Phoenix sp. was said to be intermediate between modern Phoenix dactylifera and P. reclinata (Dechamps,

1987; Dechamps and Maes, 1987). In the late Pliocene Lusso Beds of the Semliki Valley in the

Democratic Republic of the Congo (formerly Zaire), a fossil wood stem of Phoenix reclinata was reported (Dechamps and Maes, 1990). However, the specific characters that led to the assignment of Phoenix sp. were not discussed in either case.

Leaves. Read and Hickey (1972) reviewed the fossil record of palm foliage and defined six form genera they felt were appropriate for fossil palms due to the extensive morphological convergence. Because Phoenix foliage is so distinctive, Read and Hickey (1972) allowed this modern name to be used in the fossil literature (Read and Hickey, 1972; Barrow, 1998).

Leaves assigned to Phoenix have been found in Europe from the Eocene onward

(Barrow, 1998). Saporta (1878) created a new taxon based on fossil fronds and fruits,

Palaeophoenix aynardi, from Eocene material collected from Brives near Puyen-Velay, France.

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These specimens were reassigned to Phoenix by Read and Hickey (1972). Brongniart (1828) created the genus Phoenicites based on a brief description of Phoenix-like leaves (locality unclear, likely France).

Many palm fossils representing multiple species have been recovered from Messel

(Germany) including pinnate palm fronds (Schaarschmidt and Wilde, 1986; Schaarschmidt,

1992). Palm leaves rarely fall off a palm tree (though they are occasionally torn off by the wind), even after a palm has died, which could be one explanation for the limited number of palm fronds found at Messel (Schaarschmidt, 1992) and Blue Rim (S.E. Allen, personal observation) and the higher abundance of other organs, such as flowers (Burnham, 1989; Gastaldo, 1992;

Gastaldo and Huc, 1992; Burnham, 1994b).

A permineralized leaf sheath described as Phoenicicaulon mahabalei was documented from the Deccan Intertrappean bed at Umaria, District Mandla, Madya Pradesh, India (Bonde et al., 2000). Bonde et al. (2000) noted that its anatomy strongly resembled a leaf base of the Tribe

Phoeniceae because it had one large phloem vessel, two wide metaxylem vessels, and lots of fibers in the vascular bundle, in addition to dorsal and ventral sclerenchyma. Crabtree (1987) noted pinnate, induplicate palm leaf fragments without spines at the base similar to Read and

Hickey’s (1972) Phoenicites in the Lower Campanian Two Medicine Formation in northern

Montana.

Seeds. Ellipsoidal boat-shaped fossil seeds with a longitudinal raphe resembling modern date seeds (which range from 7 to 30 mm long, Barrow, 1998) have been assigned to

Phoeniceae. Phoenicites occidentalis from the late Eocene or early Oligocene Catahoula

Formation of eastern Texas displays affinities to extant Phoenix (Berry, 1914). The larger specimen of Phoenicites occidentalis was 3 cm long by 1 cm wide, and the smaller one measured

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2.5 cm by 0.8 cm (Berry, 1914). Berry (1914) also found a cast of the fruit, palm foliage fragments, and palm stems at this locality. A seed that compared favorably to Phoenix from the early Miocene Hiwegi Formation, Rusinga Island, Kenya was recorded as the only monocot representative at that site (Pan et al., 2006; Collinson et al., 2009). Two seeds (the larger 2 by 1.5 cm) resembling Phoeniceae were reported in a dinosaur coprolite from the Late Cretaceous

Lameta Formation in Pisdura, Maharashtra, India (Ambwani and Dutta, 2005). Characters including the seed shape, size, and the lateral position of the embryo suggested affinities with the

Phoenicoid palms (Ambwani and Dutta, 2005). Other fossil seeds assigned to Phoenix include

Phoenix hercynica Mai (20 mm by 6 mm) from the middle Eocene Geiseltal basin of Germany

(Mai, 1976), and Phoenix bohemica Bůžek from the lower Miocene of Central Europe (Bůžek,

1977). Phoenix bohemica varies from 1.2 to 2 cm long and 8 to 10 mm wide (Bůžek, 1977).

However, no similar seeds have been observed as of yet in any of the Bridger, Green River, or

Wind River localities.

Flowers and pollen. Fossil flowers with affinities to Phoenix are prevalent in Europe.

Phoenix eichleri from the middle Eocene (~44.1 ± 1.1 Ma, see age discussions and citations within Engel, 2001) Baltic Amber of Germany was documented by Conwentz (1886). Conwentz

(1886) noted that the flowers were usually male or female (a reasonable conclusion because the genus is dioecious). In addition, this amber flora preserved many other flower taxa indicating the taphonomic conditions were favorable for delicate material. However, Daghlian (1981) was dubious of Conwentz’s assignment of these flowers to Phoenix because of the stamen morphology, but did not elaborate as to why.

Many monoecious palm flowers have been recovered from Messel, Germany

(Schaarschmidt and Wilde, 1986; Schaarschmidt, 1992; Harley, 1997). The flowers are

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actinomorphic and range from 7-9 mm in diameter. They have three long valvate petals and three sepals that are half or less than half the length of the petals (Harley, 1997). The flowers and in situ pollen are aligned with Coryphoideae and have similarities to Phoenix. Pollen extracted from the stamens of these flowers was placed into two species in the fossil genus

Palmaemargosulcites Harley (1997). The pollen was monosulcate, ellipsoid, and ranged from 22

– 32 µm in diameter. The sulcus was slightly shorter than the long axis.

Chandler (1957) documented male palm flowers (some with in situ pollen) assigned to

Calamus daemonorops (Ung.) from near Mudeford in southern England. Spines, fruiting axes, and seeds were also found at this locality (Chandler, 1957).

Phoenix windmillis also shows affinities to Statzia divaricata (Wess. & Web.) Weyland

(Weyland, 1937) from the Oligocene of Rott, Germany. However, S. divaricata has short broad rounded petals that are very wide at the base. The figured S. divaricata specimens display a tricarpellate ovary, pointed sepals, and striated petals. Weyland (1937) inferred that the plants were dioecious and only observed evidence for three anthers (in contrast to the six on P. windmillis).

Statzia divaricata flowers are consistently ~3 mm wide, which is significantly smaller than P. windmillis. While S. divaricata was not placed into a family, Weyland did place it with the dicotyledonous taxa, which was likely an oversight.

A pollen grain of the Phoenix reclinata-type was documented from a well in the Lokichar

Basin in northern Kenya (Vincens et al., 2006). It was found in a pollen assemblage in the late

Oligocene to early Miocene Lokhone Shale Member of the Lokhone Formation (Vincens et al.,

2006) and is the earliest known record of Phoenix in Africa (Pan et al., 2006).

In the New World, Poinar (2002) assigned fossil palm flowers in amber from the

Paleogene of the Dominican Republic to Trithrinax dominicana in the Thrinacinae tribe of the

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Coryphoideae. This was the first fossil record of this genus. The flowers were heterosexual with three petals, three sepals and six stamens with broad filaments. In addition to being heterosexual,

T. dominicana differed from P. windmillis most obviously because it had long filaments and semi-globose anthers (Poinar, 2002). Poinar (2002) also documented a fossil palm flower assigned to the Iriarteinae of the Arecoideae from Mexican amber. This was noteworthy because of the presence of at least 50 stamens (Poinar, 2002).

Phoenix windmillis also shows affinities to fossil morphotypes found at the Oligocene

Los Ahuehuetes locality in the Coatzingo Formation, near Tepexi de Rodríguez, Puebla, Mexico

(S.R. Manchester, Sergio R.S. Cevallos-Ferriz, and Laura Calvillo-Canadell, personal communication, February-March, 2015; Magallón-Puebla and Cevallos-Ferriz, 1994a, b, c;

Beraldi-Campesi et al., 2006; Silva-Romo, 2010). However, differences include broader, stouter petals with obvious striations in the Mexican material. In addition, there are around 500 specimens of the Mexican morphotype and none have stamens. The Mexican flowers have three whorls with the center being a tri-carpellate ovary (Sergio R.S. Cevallos-Ferriz and Laura

Calvillo-Canadell, personal communication, December 2013). It is possible that the Mexican specimens represent the carpellate flowers, while Phoenix windmillis represents the staminate flowers, but the differences in the petal morphology are significant enough to suggest different taxa.

In documenting the pollen of the Eocene Green River Formation, Wodehouse (1933) mentioned four species of Arecaceae including Arecipites punctatus. He noted that this pollen matches that of Phoenix dactylifera except that the fossil grains were slightly larger than the grains of extant P. dactylifera (Wodehouse, 1933). However, Nichols (2010) reexamined all of

Wodehouse’s original material and made some updates. While he thought that Arecipites

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punctatus could be assigned to some species in Arecaceae, he did not specifically agree with the

Phoenix dactylifera comparison that Wodehouse made (Nichols, 2010).

Paleoclimate Implications

The North American paleobotanical record, along with numerous other paleoclimate proxies, supports significantly warmer conditions with rare to no frost as far north as southwestern Canada around 50 Ma based on the presence of palms, gingers, cycads, and tree ferns (Wing and Greenwood, 1993). These plant groups can be used to estimate past minimum temperatures based on their growing requirements today as they are all restricted to mild climates with rare frost (Wing and Greenwood, 1993). The presence of Phoenix windmillis in the Eocene of the Rocky Mountains adds further support to this well-documented hypothesis.

Palms and other frost-intolerant taxa like gingers and cycads have manoxylic “wood.”

That is, their stems have numerous parenchyma cells mixed in with the xylem cells which create a softer, water-rich stem that is very susceptible to frost. Exposed meristems, buds, leaves, and roots are all easily damaged by frost (Wing and Greenwood, 1993; Greenwood and Wing, 1995).

While palm seeds are very resistant to frost, germinating seeds and young seedlings are more susceptible (Larcher and Winter, 1981; Sakai and Larcher, 1987). For example, Phoenix canariensis, which is found as far north as the Canary Islands and Madeira to the west of

Morocco, experiences initial frost damage to its leaves at -9ºC as an adult and at -6ºC as a seedling. Parts of the leaves are killed at -10.5ºC in adult Phoenix canariensis and at -7.5ºC in the seedlings (Larcher and Winter, 1981; Sakai and Larcher, 1987). However, palm roots are even more susceptible to frost than the foliage with ground frost causing severe damage and frequent death (Larcher and Winter, 1981; Sakai and Larcher, 1987). In following what is known of extant Phoenix, it is reasonable to assume that Phoenix windmillis would also experience root damage with any ground frost and damage to the aerial parts of the plant starting at around -6ºC.

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Conclusions

The fossil flowers resemble those of extant Phoenix L. (Coryphoid Arecaceae) because of the number of perianth parts and stamens, and the elongate anthers. The in situ fossil pollen is also commensurate with extant Phoenix in size, aperture number, and surface sculpturing. The presence of Phoenix windmillis in the Rocky Mountains of the Eocene provides additional support for paleoclimatic conditions with rare to no frost. The occurrence of these flowers in the

Eocene of the Rocky Mountains greatly expands the past range of Phoenix from its current Old

World native distribution.

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Figure 4-1. Map of localities in southwestern Wyoming, northeastern Utah, and northwestern Colorado where Phoenix windmillis sp. nov. flowers have been found.

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Figure 4-2. Phoenix windmillis sp. nov. from the Blue Rim flora of the Bridger Formation (A-D), the Wind River Formation (E), the Parachute Creek Member of the Green River Formation (F-H), and the Laney Member of the Green River Formation (I-K) showing three petals, three sepals, and remnants of the six stamens. A) Flower showing three petals and fragments of anthers, UF15761N-57367, B) Flower showing central circular area from which the petals arise, UF15761N-57356, C) UF15761N- 57365, D) UF15761-22608, E) Composite image of the part and counterpart, DMNH EPI.32900, F) Flower with a full set of six stamens (indicated by the black arrows), UCMP 391008, G) UF00579-060660, H) Flower clearly showing the two whorls of perianth, USNM 608674, I) UF18151-56380, J) Specimen showing the well-defined central circular disk (arrow); UF18150-56377, K) Holotype specimen with in situ pollen (Fig. 4-4) UF18150-56374. Scale bars = 0.5 cm, except in K = 4 mm2.

2 Note that this is a correction of an error in the original manuscript where it indicated all scale bars = 5 mm.

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Figure 4-3. Phoenix windmillis sp. nov. from the Fossil Butte Member of the Green River Formation, showing well preserved elongate anthers, triangular sepals, and elongate petals. Note that the petals are more slender than in most specimens from others sites (Fig. 4-2). A) UF00319-56781, B) FMNH PP55104. Scale bars = 0.5 cm.

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Figure 4-4. Pollen from UF18150-56374. A) Anther fragment viewed by epifluorescence. Scale bar = 200 µm; B) In situ pollen grains viewed by epifluorescence. Scale bar = 20 µm; C-E) Pollen viewed by light microscopy. Scale bars = 20 µm; F-K) Pollen viewed by scanning electron microscopy. Scale bars: F = 12 µm, G = 8.57 µm, H = 10 µm, I = 12 µm, J = 20 µm, K = 3.75 µm.

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Figure 4-5. Extant Phoenix flowers and pollen for comparison to fossil material. A-C) Phoenix cf. canariensis Chabaud from the University of Florida Herbarium (FLAS). Collected in August 2004 in Kanapaha Botanical Gardens, Gainesville, FL by S. Barry Davis #1158. A) FLAS 213195. B) FLAS 213196. C) Flower with central circular disk, which is also seen on many of the fossil specimens, FLAS 213195. Scale bars (A-C) = 0.5 cm. D-F) Light microscopy images. D & E) Phoenix reclinata Jacq., MO 2094073, Ghana. These are the same grain at different focal lengths. F) Phoenix dactylifera L., BH Bailey and Bailey, CA, USA. Scale bars (D-F) = 20 µm.

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CHAPTER 5 ICACINACEAE FROM THE EOCENE OF WESTERN NORTH AMERICA

The early and middle Eocene biota of western Wyoming, partially treated in studies by

Lesquereux (1878, 1883), Newberry (1898), Berry (1930), Brown (1929, 1934, 1937),

MacGinitie (1974), and Wilf (2000), is characterized by some of its more common floristic elements, including Macginitiea wyomingensis (MacGinitie) Manchester (Platanaceae), Populus cinnamomoides (Lesquereux) MacGinitie (Salicaceae), Cedrelospermum nervosum (Newberry)

Manchester (Ulmaceae), and abundant Lygodium kaulfussii Heer (Schizaeaceae). However, many accessory elements of the flora remain poorly known and/or misidentified. New investigations of the Bridger Formation flora of southwestern Wyoming, in comparison with the previously studied Kisinger Lakes flora of the Aycross Formation in northwestern Wyoming

(MacGinitie, 1974), are aimed at a better understanding of the floristic affinities of the biota, which includes a mixture of extinct and extant genera. The Icacinaceae Miers represent a biogeographically and ecologically significant component of the flora, given the family’s present-day confinement to tropical forests.

The Icacinaceae are a pantropical family of woody trees, shrubs, and climbers including ca. 34 genera and 200 species, as currently circumscribed (Stevens, 2001 onward; APG, 2009;

Byng et al., 2014), although this likely does not represent a monophyletic assemblage (Kårehed,

2001; Byng et al., 2014). The family is phylogenetically positioned near the base of the lamiid clade (Kårehed, 2001; Soltis et al., 2011; Refulio-Rodriguez and Olmstead, 2014), close to

Garryales, Oncotheca Baill., and Metteniusa Karsten. Traditionally, the family (Icacinaceae s.l.) included around 54 genera and 400 species, which were organized by different authors into

 Reprinted with permission from: ALLEN, S.E., G.W. STULL, AND S.R. MANCHESTER 2015. Icacinaceae from the Eoence of western North America. American Journal of Botany 102: 725-744. © 2015 by the Botanical Society of America.

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either tribes (Icacineae, Iodeae, Phytocreneae, and Sarcostigmateae; Engler, 1893) or informal groups (Bailey and Howard, 1941a, b) based largely on stem and wood anatomical features.

Multiple phylogenetic studies (Savolainen et al., 2000; Soltis et al., 2000; Kårehed, 2001) have shown this traditional circumscription to be highly polyphyletic; consequently, approximately 20 genera, from the Icacineae tribe of Engler (1893), or groups I and II of Bailey and Howard

(1941b), were removed from the family and transferred to the campanulid families

Cardiopteridaceae Blume (Aquifoliales), Pennantiaceae J. Agardh (Apiales), and Stemonuraceae

Kårehed (Aquifoliales). Recent analyses based on ca. 73 plastid genes indicate that additional genera (e.g., Apodytes E. Mey. ex Arn., Calatola Standl., Platea Blume, Emmotum Desv.) should be removed from the family and included within a broader circumscription of Metteniusaceae H.

Karst. ex Schnizl. (G. W. Stull et al., unpublished manuscript1). The remaining 23 genera, including all genera of the traditional Iodeae, Phytocreneae, and Sarcostigmateae tribes, and some genera of the Icacineae (e.g., Cassinopsis Sond., Icacina A. Juss, and Mappia Jacq.), constitute the Icacinaceae s.s. (G. W. Stull et al., unpublished manuscript), which corresponds approximately to the Icacina group of Kårehed (2001). Although the monophyly of the constituent genera has not been investigated comprehensively, recent analyses show that the monotypic genus Polyporandra Becc. is nested within Iodes Blume, and that the genera

Polycephalium Engl. and Chlamydocarya Baill. are nested within Pyrenacantha Wight (Byng et al., 2014).

The Icacinaceae s.s. have a rich fossil record, primarily from the Paleogene of North

America and Europe, although new fossil evidence from South America (Stull et al., 2012),

1 Manuscript was published after this one, final citation for G.W. Stull et al., unpublished manuscript is: STULL, G. W., R. DUNO DE STEFANO, D. E. SOLTIS, and P. S. SOLTIS. 2015. Resolving basal lamiid phylogeny and the circumscription of Icacinaceae with a plastome-scale data set. American Journal of Botany 102: 1794-1813.

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Africa (Manchester and Tiffney, 1993), and Asia (endocarp from the Miocene Wenshan flora of southeastern Yunnan, China; specimen in XTBG collection of Zhekun Zhou) has been emerging.

The fossil record of the family consists primarily of endocarps (drupaceous fruits characterize the family). The endocarps are woody, unilocular, lenticular to globose in cross section, and contain a single seed, as only one of the two apical ovules present in each ovary matures

(Kårehed, 2001). The ovules are supplied by a vascular bundle that generally runs along one margin of the fruit (usually in the mesocarp) and passes through the endocarp to the locule subapically, below the stylar canal (Reid and Chandler, 1933; Howard, 1942). In the older literature (Reid and Chandler, 1933; Howard, 1942), the main vascular bundle of icacinaceous fruits is referred to, perhaps incorrectly, as a funicle, a term typically used to specifically denote the stalk connecting an ovule to the placenta (Eames, 1961). The overall morphology and surface sculpture of the endocarp vary within the family and, in combination with other internal morphological features, often are useful for recognizing particular genera or putative clades in the fossil record (Stull et al., 2012). The modern genus Iodes (including Polyporandra), for example, is unique within the family in having the marginal/main vascular bundle embedded within the endocarp wall, in addition to having a reticulately ridged endocarp surface (Fig. 5-1).

We describe fossils of Icacinaceae from the Eocene of Wyoming, Utah, Colorado, and

Oregon representing three species based on fruits and one based on leaves. Biceratocarpum brownii gen. et comb. nov. accommodates endocarp compressions/impressions, casts, and molds with distinctive subapical horn-like structures from the early–middle Eocene Aycross and

Bridger Formations, the Clarno Formation, and the Parachute Creek Member of the Green River

Formation. Icacinicaryites lottii sp. nov. is based on endocarp compressions/impressions from the Aycross Formation of northwestern Wyoming. Iodes occidentalis sp. nov. is based on

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endocarp compressions/impressions from the early–middle Eocene Bridger Formation and the

Laney Member of the Green River Formation of southwestern Wyoming and rare, similarly preserved specimens from the Parachute Creek Member of the Green River Formation in northwestern Colorado. Finally, we describe fossil leaves from the Bridger Formation with affinities to Iodes that co-occur at multiple localities with Iodes occidentalis, suggesting that they might belong to the same taxon. However, because numerous other angiosperm groups show leaf architecture similar to Iodes, we describe the leaves as a new species of Goweria Wolfe (G. bluerimensis sp. nov.), a fossil leaf genus attributed to Icacinaceae but with uncertain intrafamilial affinities.

We discuss the systematic implications of these fossils and call attention to logical issues surrounding the placement of fossils within the traditional Iodeae tribe, which is likely polyphyletic and defined mainly on plesiomorphic fruit characters. We also discuss the biogeographic significance of the fossils in the context of the broader fossil and modern distribution of the family, focusing in particular on Iodes, which today is restricted to tropical forests of Africa, Madagascar, and Indo-Malesia, and Biceratocarpum brownii, which shows strong morphological similarity to the Eocene London Clay taxon “Iodes” corniculata Reid &

Chandler.

Materials and Methods

The fossils examined for this work derive mainly from four Eocene outcrop areas in western Wyoming (Fig. 5-2). Most specimens (fruits and leaves) were found at sites along the

Blue Rim escarpment in southwestern Wyoming (UF localities 15761, 15761N, 15761S, 18288,

19031, 19032, 19225, 19225N, 19337, and 19338). The Blue Rim sites are situated in the lower part of the Bridger Formation (Kistner, 1973; Allen, 2011), representing mostly fluvial and lacustrine environments, and are estimated to be ~49.5 Myr old. Other fruits were collected from 358

the Aycross Formation, from localities constituting the Kisinger Lakes flora of MacGinitie

(1974), in northwestern Wyoming (USGS loc. D3532A-D, UCMP loc. PA108 [A], PA121 [B];

UF localities 19376, 19377). This flora is preserved in fluvial to floodplain environments and is estimated to be ~48.5 Myr old. Specimens were also studied from the Tipperary site, investigated by Berry (1930) and MacGinitie (1974; USGS loc. 8785, UCMP PA110). We also collected from the Barrel Springs localities in the Laney Member of the Green River Formation, in southern Wyoming (UF localities 18151, 19335). Other specimens were found in collections from the Parachute Creek Member of the Green River Formation in northwestern Colorado (UF loc. 00582 and DMNH loc. 317) and near Bonanza, Utah (UF loc. 00583). A specimen collected by David Kohls in 2001 in the Green River Formation is also included (USNM loc. 41142,

Denson). Specimens from the Clarno Nut Beds site in the Clarno Formation in Wheeler County,

Oregon, were also examined (UF loc. 00225).

The leaves and fruits were recovered by splitting shales and siltstones in the field with additional fine preparation in the laboratory to expose them more fully. Fossil leaves were photographed with a Nikon D300 camera. Fruits (both macro and close-ups) were photographed with a Canon EOS Digital Rebel XSi camera. Measurements of morphological characters were done by hand or using the program ImageJ (Rasband, 1997-onwards). The density of papillae on the fossil and modern fruits was assessed from light microscopy images of the specimens by counting them in the program Adobe Photoshop (San Jose, California, USA), and calculating the distance between adjacent papillae with ImageJ.

Herbarium specimens examined for comparison are listed in Tables 5-1 and 5-2. Fossil and modern leaves were described using the terminology described in the Manual of Leaf

Architecture (Ellis et al., 2009). The cleared leaves figured for comparison are from the National

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Cleared Leaf Collection (NCLC) housed at the Smithsonian Museum of Natural History in

Washington, D.C.

Systematics and Results

Family—Icacinaceae Miers 1851.

Genus—Biceratocarpum Stull, S.E. Allen, & Manchester, gen. nov.

Diagnosis—Endocarp ellipsoidal in lateral view, lenticular in cross section, unilocular, bivalved.

Outer endocarp surface with a reticulum of ridges delimiting polygonal areoles with few or no freely ending ridgelets. Endocarp possessing an eccentric, subapical pair of horn-like protrusions, with one on either face of the endocarp surface.

Etymology—The genus name Biceratocarpum means fruit with two horns (based on the Latin components bi- = two, cerato- = horn, and -carpum = fruit), and refers to the distinct pair of horn-like protrusions shown by the fossils.

Species—Biceratocarpum brownii (Berry) Stull, S.E. Allen, & Manchester, comb. nov.

Basionym—Carpolithus browni Berry 1930, USGS Prof. Paper 165-B, pp. 78–79, pl. 14, Fig. 1.

The original specific epithet, browni, was indicated with one “i” at the end. However, we have emended this to brownii following the practice that if a name ending in a consonant is used for a specific epithet, “ii” should be used (Stearn, 2004).

Emended diagnosis—Endocarp ellipsoidal in lateral view, lenticular in cross section, 7.5–9.5 mm long, 5–7.5 mm wide, unilocular, bivalved. Outer surface covered with a reticulum of ridges delimiting polygonal areoles (ca. 20–25 total) with few or no freely ending ridgelets. Course of the marginal vascular bundle embedded in the endocarp wall. Endocarp possessing a symmetrical pair of horn-like protrusions, positioned eccentrically and subapically on the outer endocarp faces, each apparently accommodating a central channel. Inner endocarp surface showing shallow mounds corresponding to areoles/depressions of outer endocarp reticulum. 360

Inner endocarp surface densely covered with regularly spaced, minute papillae; papillae average

0.03 mm apart (from 10 measurements done at random from punctae of the locule cast from specimen USNM 316745). Endocarp wall 0.3–0.4 mm thick (cellular detail not preserved as the wall is generally coalified).

Holotype—USNM 316745 (pl. 14, Fig. 1 in Berry, 1930; Figs. 5-3D, E, 5-4A in present article).

Type locality—Tipperary flora, Wyoming (USGS loc. 8785).

Additional localities—Kisinger Lakes, Wyoming; Blue Rim, Wyoming; Bonanza, Utah; Clarno

Nut Beds, Oregon; Douglas Pass, Colorado.

Additional specimens—UF 19376-59511, 59512, 59513 (Kisinger Lakes); UF 19225-54569,

54562 (Blue Rim), UF 00583-61314 (Bonanza); UF 00225-6458, 9902 (Clarno Nut Beds);

DMNH 317-35557 (Douglas Pass).

Discussion—This species was originally described from a single piece of shale bearing two endocarp specimens, one of them a locule cast showing the papillae, and the other a compression fossil showing the external features of the endocarp (Figs. 5-3D, E). Our diagnosis expands on that of Berry (1930) to include additional features we observed in the holotype and provides a size range based on subsequently recognized specimens. The type collection from Tipperary has been augmented with a few additional new impression specimens from the Kisinger Lakes flora

(Fig. 5-3G), which is considered to be contemporaneous (MacGinitie, 1974), and from the middle Eocene Parachute Creek Member of the Green River Formation. We also discovered two previously collected specimens from the middle Eocene Clarno Nut Beds belonging to this taxon, both of which document the position of the vascular bundle within the endocarp wall and show a pair of apical protrusions. One specimen (UF 00225-6458) was previously figured by

Manchester (1994: pl. 17, Figs. 3, 4) but misidentified as Iodes multireticulata Reid & Chandler.

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The other specimen (UF 00225-9902) is newly figured here (Figs. 5-3A, B). We prepared a line drawing based on the specimens cited to more clearly present our interpretation of the morphological features shown by this taxon (Fig. 5-5).

Biceratocarpum brownii possesses numerous characters commonly found in endocarps of

Icacinaceae: a single locule, a bivalved construction with a reticulum of ridges covering the two endocarp faces, an asymmetrical apex, and (as in some extant genera) a papillate lining on the inner endocarp surface (Fig. 5-4A). We considered other fossil and extant icacinaceous genera that might accommodate this species—however, the combination of characters exhibited by this fossil precludes placement in any of them. While Hosiea Hemsl. & E.H. Wilson, Iodes, and

Miquelia Meisn. all possess (at least in certain species) papillae on the inner endocarp walls, B. brownii differs from these genera by the presence of a pair of horn-like protrusions near the apex of the endocarp, with one on each of the two valves and thus visible in both counterparts of laterally preserved impression specimens (Fig. 5-3). On impression specimens, the horns appear as depressions, sometimes containing infillings of the channels within the horns (e.g., Figs. 5-3B,

C). These structures possibly represent the point of entry of two vascular bundles into the locule

(supplying the two apical ovules characteristic of icacinaceous fruits), although this species also has a marginal vascular bundle similar to other genera of Icacinaceae (Fig. 5-3A). It is therefore difficult to assess the possible functions of these protuberances, especially since there do not appear to be any homologous structures in modern fruits of Icacinaceae from which to draw inferences. The extant genus Phytocrene Wall. possesses a pair of endocarp channels, but these are more central and apically positioned, and they are not enveloped within protuberances as in

Biceratocarpum (Fig. 5-6). Furthermore, Phytocrene does not possess a prominent vascular bundle within the endocarp wall.

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Although the endocarp is missing from the specimen in Fig. 5-3A, the specimen does show an infilling of the vascular canal positioned within the groove left by the marginal endocarp ridge, indicating that the vascular bundle traveled through the endocarp wall. Given that the vascular bundle is embedded within the endocarp wall, it seems likely that this species is closely related to Iodes. However, as mentioned already, no extant members of Iodes possess subapical protrusions. Additionally, B. brownii is distinct in having well-defined areoles in the endocarp reticulation with few or no freely ending ridgelets. Iodes and other genera in the family with ridged endocarps (e.g., Alsodeiopsis Oliv., Desmostachys Miers., Natsiatum Buch.-Ham. ex

Arn., and Rhyticaryum Becc.) usually have at least a few freely ending ridgelets penetrating the areoles, or a more diffuse ridging pattern without well-defined areoles. Given these distinct attributes, the recognition of a new genus, perhaps related to Iodes, is warranted:

Biceratocarpum.

This fossil species was widespread, with occurrences at Kisinger Lakes (WY), Tipperary

(WY), Blue Rim (WY), Bonanza (UT), Douglas Pass (CO), and Clarno (OR). At Blue Rim, it is known from only a few specimens, in contrast to the abundant endocarps of Iodes occidentalis

(described below). At first, we compared Biceratocarpum brownii with specimens of I. occidentalis from Blue Rim to determine whether they might be conspecific, as both are reticulately ridged and have a similarly papillate locule cast. On close inspection, however, a number of differences became apparent. Iodes occidentalis appears to have had more inflated, subglobose endocarps, allowing them to orient in various ways in the sediment, whereas B. brownii tends to lie flat in the bedding plane reflecting a preferred orientation due to the originally lenticular form of the fruit. Iodes occidentalis has a more complicated ridging pattern on the endocarp, with freely ending ridgelets entering the areoles, unlike B. brownii.

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Furthermore, I. occidentalis lacks the pair of horns (one on each endocarp face) shown by B. brownii and instead has a single vascular strand running through the endocarp wall, consistent with the modern genus Iodes (Fig. 5-1).

The main diagnostic character for this genus (the pair of horns) is not present in other fossil genera of Icacinaceae, such as Iodicarpa Manchester, Palaeohosiea Kvaček & Bůžek, or

Croomiocarpon Stull, Manchester & Moore. However, the combination of characters shown by

Biceratocarpum—i.e., reticulately ridged endocarps lacking or nearly lacking freely ending ridgelets, a pair of subapical horns on the endocarp, and papillae on the inner endocarp surface— are seen in the London Clay species described as “Iodes” corniculata by Reid and Chandler

(1933). Although Biceratocarpum brownii differs from “Iodes” corniculata in having more numerous areoles on the endocarp surface (20–25 instead of 15–20) and a more densely papillate inner endocarp wall, they are otherwise very morphologically similar and share the unique feature of having a subapical pair of horns. These characters suggest close affinities between these taxa, and, upon further study of the London Clay taxon, perhaps calls for transfer of

“Iodes” corniculata to Biceratocarpum. Should further study indicate that the London Clay and

Wyoming fossils are conspecific, then the earlier published epithet, brownii, would take priority.

Icacinicarya Reid and Chandler (1933) was established to accommodate fossils of

Icacinaceae lacking clear affinities to any particular modern genus. Given that Icacinicarya was originally established based on permineralized material, Pigg et al. (2008) established

Icacinicaryites to serve a similar function for fossils lacking the anatomical details necessary for a more precise generic assignment. We considered placing this species in the latter genus, but B. brownii is sufficiently preserved and morphologically distinct enough to warrant placement in a separate fossil genus.

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Genus—Icacinicaryites Pigg, Manchester & DeVore 2008.

Species—Icacinicaryites lottii Stull, S.E. Allen, & Manchester, sp. nov.

Diagnosis—Endocarp elliptical with a reticulum of ridges forming polygonal areoles with occasional freely ending ridgelets. Apex with a sessile and button-shaped stigma. Fruit subtended by a thick stalk.

Holotype hic designatus—UF 19376-59514 (Fig. 5-7A).

Type locality—Kisinger Lakes, Wyoming (UF loc. 19376).

Paratype—UF 19376-59515 (Figs. 5-7B, C).

Etymology—The specific epithet is named for FLMNH paleobotany research assistant and laboratory manager Terry Lott, who collected these specimens in the summer of 2013.

Description—Endocarp elliptical, 9.8–12.1 mm long, 8.7–8.8 mm wide. Base and apex relatively symmetrical. Surface covered with a reticulum of ridges forming polygonal areoles (ca. 35 per endocarp face). Areoles penetrated by unbranched (or occasionally once-branched) freely ending ridgelets. Exocarp and mesocarp 0.9–1.1 mm thick, represented by a narrow, darkly stained layer surrounding the endocarp impressions/compressions, with a sessile, button-shaped stigma evident at the apex. Stigma 1 mm wide. Fruit subtended by a thick stalk, ca. 1.1–1.7 mm wide and 3.3–4.3 mm long.

Discussion—This species is represented by two specimens collected from the Kisinger Lakes flora in Fremont County, Wyoming. These fossils are unique in that the exterior portions of the fruit (as opposed to just the endocarp) are at least partially preserved. The endocarp compressions/impressions are surrounded by a dark band, interpreted as the exo/mesocarp, with a button-like structure positioned at the apex of the fruit, interpreted as a sessile stigma. At the base of the fruit is a broad, obliquely angled stalk extending down from the dark layer (i.e., exo-

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and mesocarp) encompassing the fruit (Figs. 5-7A–C). This stalk probably represents either a pedicel or a stipe, with at least three lines of evidence favoring the latter interpretation: One, this structure is unusually broad compared to the pedicels of modern taxa of Icacinaceae. Two, there is no indication of perianth at the junction of this structure with the rest of the fruit, which would be expected if this structure were indeed a pedicel. Instead, it appears to be continuous with the exocarp, perhaps with a nectar disc or perianth scar at its base (Fig. 5-7A). It is possible that the perianth could have been lost during fruit development, but the perianth is almost always persistent in mature fruits of Icacinaceae (G. W. Stull, personal observations, based on numerous herbarium specimens across all genera of the family). Three, the oblique orientation of the structure suggests a lack of rigidity, which is unusual for pedicels of Icacinaceae. Although stipes are rare in Icacinaceae, they do occur in species of several genera—e.g., multiple species of

Pyrenacantha from Madagascar (e.g., Labat et al., 2006) and Miquelia caudata King (G. W.

Stull, personal observations)—and these structures on the fossils resemble the stipes present on modern species of Icacinaceae.

The combination of characters exhibited by these fossils clearly suggests affinities with

Icacinaceae and calls for the recognition of a new species. However, several key characters are unobservable, making its affinities at the generic level obscure. The reticulately ridged endocarp surface, with numerous areoles penetrated by freely ending ridgelets, closely resembles numerous modern and fossil taxa of Icacinaceae. The presence of a sessile, button-like stigma is also consistent with numerous genera within the family. Although these fossils superficially resemble Iodes, their preservation makes it impossible to determine whether they had vascular bundles inside or outside the endocarp wall and whether they had smooth or papillate inner endocarp surfaces. Furthermore, while the fossils possess structures similar to stipes of some

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species of the extant genera Pyrenacantha and Miquelia, the surface morphology of the fossils is clearly distinct from those genera in being ridged rather than pitted. Given the unclear generic affinities of these fossils, we place them in the fossil genus Icacinicaryites, which was established by Pigg et al. (2008) to accommodate compression/impression fossils of Icacinaceae lacking the preservation necessary for assignment to a more natural (i.e., presumably monophyletic) extant or fossil genus.

These fossils are distinct from Biceratocarpum brownii in lacking the pair of subapical horns on the endocarp surface and in the presence of numerous freely ending ridgelets on the endocarp surface. They are distinct from Iodes occidentalis both in their larger size (9.8–12.1 mm long in Icacinicaryites lottii vs. 7.1 mm long on average in Iodes occidentalis) and their possession of a large stipe (I. occidentalis appears to lack stipes and have relatively narrow pedicels, consistent with modern species of Iodes). The combination of a ridged endocarp surface with a prominent stipe is also a unique combination of characters not known in any other modern or fossil species of Icacinaceae.

Genus—Iodes Blume 1825.

Species—Iodes occidentalis S.E. Allen, Stull, & Manchester, sp. nov.

Diagnosis—Endocarp bivalved, globose to lenticular, with a reticulum of ridges forming irregular areoles that are regularly penetrated by freely ending ridgelets. Endocarp inner surfaces or locule casts, when preserved, densely covered with minute papillae. Vascular bundle embedded in the endocarp wall.

Holotype hic designatus—UF 19225-57242 (Figs. 5-8D, E).

Type locality—Blue Rim, Wyoming (UF loc. 19225).

Paratypes—UF 19225-57241 (Fig. 5-8F), UF 19225-57243 (Figs. 5-8G, H).

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Additional specimens examined for species description—UF 15761-22676 to 22679, 22689,

22692, 22694, 22697, 30925, 31009, 48449, 48450, 48453, 48454, 48457, 48591, 48603; UF

15761S-57858; UF 19032-39002, 39007; UF 19225-51995, 51997, 54563, 54564, 54566; UF

19337-58058; UF 19338-58269, 58271.

Etymology—The specific epithet occidentalis (Latin = western), refers to the occurrence of this species in the western hemisphere, contrasting with the modern distribution of the genus in

Africa and Asia.

Description—Endocarp globose to lenticular (may be partially due to compression), averaging

7.1 mm long by 6.2 mm wide with an average length to width ratio of 1.2:1 (based on measurements from 28 specimens), unilocular, bivalved. Base and apex usually symmetrical, rarely slightly asymmetrical (Figs. 5-8, 5-9). If asymmetrical usually at the apex. Outer surface covered with a reticulum of ridges, forming polygonal areoles (average of 25.9 areoles on each lateral face based on 19 specimens). Areoles irregular in size and shape, often penetrated by freely ending, usually unbranched, ridgelets. Longitudinal ridges present in many specimens, although commonly only moderately well developed (e.g., only run 3/4 the length of the endocarp or follow an irregular course). Specimens have an average of 3.8 longitudinal ridges

(including partial length ridges) per valve. Inner endocarp surface reflects ridging pattern of the external surface (visible on the locule casts). Locules, when well preserved, densely covered with minute papillae; spacing of papillae varied between the two specimens that are well preserved

(the papillae are most obviously represented by little holes densely covering the locule casts).

Ninty-nine papillae were counted in 0.25 mm2 on specimen UF 19225-57243 (Fig. 5-4C), while

188 papillae were observed in 0.25 mm2 on specimen UF 15761-22704 (Fig. 5-4B).

Correspondingly, spacing between adjacent papillae (measured from the center of one hole to

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another) varied with an average of 0.05 mm for specimen UF 19225-57243 and 0.03 mm for specimen UF 15761-22704 (from 10 measurements at random). Endocarp wall averaged 0.64 mm thick on specimen UF 19225-57242 (widest near the apex; cellular detail not preserved as the wall is generally coalified). Vascular bundle running through the thickness of the endocarp wall from the base to the apex, where it abruptly turns and enters to the locule (rarely preserved, but documented by an infilling of the vascular canal within the width of the endocarp wall in specimen UF 19225-57242; Figs. 5-8D, E). Pedicel occasionally preserved. On specimen UF

19225-57241 (Fig. 5-8F), the incomplete length of the pedicel is 3.3 mm, while the width is ~0.6 mm.

Discussion—The suite of characters shown by these fossils indicates that they belong to family

Icacinaceae and more specifically to the extant genus Iodes. Numerous genera in the family (e.g.,

Alsodeiopsis, Desmostachys, Hosiea, Iodes, Natsiatum, Rhyticaryum) have woody, bivalved, unilocular endocarps, covered by a reticulum of ridges on the external surface, with an asymmetrical apical bulge marking the entry of the main vascular bundle into the locule (Stull and Manchester, 2012). This vascular bundle is called the funicle in earlier literature on fossil and modern Icacinaceae (e.g., Reid and Chandler, 1933; Howard, 1942). This suite of fruit characters has generally been associated with the Iodeae (Engler, 1893; Sleumer, 1942), including the genera Hosiea, Iodes, Mappianthus Hand.-Mazz, and Natsiatum, and paleobotanists have generally placed fossil fruits with this set of characters in this tribe (e.g.,

Reid and Chandler, 1933). However, molecular data (Byng et al., 2014; Stull et al., in prep.) indicate that the Iodeae are not monophyletic. Additionally, several genera outside the tribe (e.g.,

Alsodeiopsis, Desmostachys, Rhyticaryum) have fruit characters similar to genera within the

Iodeae tribe (Stull and Manchester, 2012). These findings suggest that certain “Iodeae” fruit

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characters may be plesiomorphic or homoplasious and consequently unreliable for generic identification. Paleobotanists should therefore no longer assign fossils to this tribe because it does not seem to represent a natural group.

Despite issues surrounding the monophyly of the Iodeae and their recognition in the fossil record, several genera historically placed within this tribe appear themselves to represent monophyletic lineages and possess unique character combinations allowing identification in the fossil record. Iodes, for instance, is unique among icacinaceous genera in that the main vascular bundle of the fruit—which, as mentioned earlier, runs from the base of the fruit to the apex, where it enters the locule to provide nutritional supply to the apical ovules—is embedded within the endocarp wall (Fig. 5-1). All other extant genera within the family possess vascular bundles that run through the mesocarp, along the outside of the endocarp. Fruits of Iodes also commonly have papillae lining the inner wall of the endocarp, as do the fossil specimens described here.

However, not all extant species of Iodes possess papillae on the inner endocarp wall surfaces [G.

W. Stull, personal observations: Iodes balansae Gagnep., papillae absent, KUN 0647596; Iodes seguinii (H. Lév.) Rehder, papillae absent, KUN 0649120]. It is also important to recognize that several other genera of Icacinaceae possess species with papillate inner endocarp walls (e.g.,

Miquelia, Hosiea). Therefore, this character alone does not permit definitive identification of

Iodes, although in combination with others characters (especially an embedded vascular bundle) it appears useful for identifying this genus.

On the basis of an examination of modern fruits of Iodes (Table 5-1), the fossil fruits described here are somewhat more similar to the African species. The fruits of modern African species, like Iodes occidentalis, tend to be smaller (<15 mm long), occasionally somewhat globose, with a more regular reticulation pattern consisting of closed areoles and freely ending

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ridgelets (Fig. 5-1). The Asian species, on the other hand, tend to have larger fruits (15 to 40 mm long) that are lenticular in cross section with a more diffuse ridging pattern on the endocarp surface. Furthermore, multiple Asian species have a small cleft toward the base of the endocarp, a feature absent from our fossils.

Iodes occidentalis differs from previously described fossils of Iodes (Reid and Chandler,

1933; Manchester, 1994; Tiffney, 1999) in having a more globose shape and in having the areoles of the endocarp reticulation consistently penetrated by freely ending ridgelets (usually unbranched). The endocarp surface of I. chandlerae is unknown, however, because this taxon was described based on locule casts, making comparison with our new species more challenging.

The locule surfaces of Celtis L. fruits, with which fossil Iodes fruits are sometimes confused, are smooth and therefore do not leave an impression of ridging on locule casts. The locule surfaces of Celtis endocarps also lack papillae.

Genus—Goweria Wolfe.

Species—Goweria bluerimensis S.E. Allen, Stull, & Manchester, sp. nov.

Diagnosis—Leaves simple, ovate to elliptical in shape, unlobed, and untoothed margin. Base angle >90°. Primary venation pinnate, secondaries brochidodromous, ≥5 prominent veins radiating from the base of the laminae. Intersecondaries absent, tertiary veins percurrent.

Holotype hic designatus—UF 15761N-57228 (Fig. 5-10A).

Type locality—Blue Rim, Wyoming (UF loc. 15761N).

Paratype—UF 15761-55239 (Fig. 5-10C).

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Additional specimens examined for species description—UF 15761-22732, 48468, 55240,

55241, 55242, 55243, 55244, 55253; UF 15761N-61357; UF 19032-39006; UF 19225-51975,

57111.

Specimens included in the leaf mass per area (MA) analysis—UF 15761-22732, 48468, 55240,

55241, 57271; UF 15761N-57228, 57278; UF 15761S-57861, 57865; UF 19032-38992, 38996,

39001; UF 19225-56980, 57111, 59595; UF 19225N-57958; UF 19337-58054; UF 19338-

58375.

Etymology—The specific epithet bluerimensis refers to the escarpment in the Bridger Formation of southwestern Wyoming where these leaves have been found.

Description—Petiole 2 to 7.5 mm long (when preserved, often incomplete) and ~1.5 to 2.5 mm wide, frequently showing a darker strand of tissue down the center of the petiole (see Fig. 5-10A,

I2). Lamina (leaf blade) varies from nanophyllous to mesophyllous (1.3 to 8.5 cm long and 0.6 to

5.0 cm wide) with length usually longer than width. Lamina relatively wide; length to width ratio on six mostly complete specimens from 1.35:1 to 1.92:1 (mean 1.68:1). One especially broad specimen has a length to width ratio of 0.82:1 (Fig. 5-10E). Shape is usually ovate but varies to elliptic. Laminae are generally symmetrical (occasionally base is slightly asymmetrical) and are unlobed and untoothed. Apex generally acute, rarely obtuse; apex shape varies from straight (the most common condition) to convex to rounded. Base convex to rounded to cordate, with basal angle ranging consistently from obtuse to reflex. Well-preserved specimens with a complete apex display a mucronate-like projection of the midvein at the apical termination (Fig. 5-10A).

Some specimens have numerous evenly spaced pigmented dots scattered across the leaf surface that may be interpreted as laminar glands or trichome bases.

2 This Figure reference erroneously said Figure 8, not 10 in the published manuscript.

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Primary venation pinnate, with a straight, moderately thick midvein. Naked basal veins present with at least five basal veins. Agrophic veins simple. Secondaries brochidodromous, but loop so close to the margin they can easily be mistaken for craspedodromous. Interior secondaries absent, while minor secondaries are simple brochidodromous. Leaves have a marginal secondary vein (which is a vein of secondary gauge running on the leaf margin, this is not to be confused with a fimbrial vein which is a marginal vein of tertiary gauge, Ellis et al.,

2009). Secondary veins are spaced closer together proximally (toward the base) with occasional irregular variations in spacing. The angle of departure of secondary veins from the midvein ranges from ~30 to over 90 with higher values near the base. Secondary angle varies from smoothly to abruptly increasing proximally (toward the base of the lamina). The center and apical portions of the leaf have a secondary vein angle to the midvein that averages to 43.9

(based on three measurements each on eight leaves), while the basalmost vein measured averaged to a significantly larger 74.8. Attachment of major secondaries to midvein excurrent

(no deflection of course). Intersecondary veins absent. Tertiary veins percurrent, mostly opposite, rarely alternate, variable in course, most frequently straight. Tertiary vein angle generally consistent, but varying from increasing exmedially, basally concentric, to increasing proximally. Epimedial tertiaries (intersect primary vein) opposite percurrent, rarely alternate, and perpendicular to the midvein. Exterior tertiaries looped. Higher order venation rarely well preserved but 4th and 5th order venation appears reticulate.

Comparison to extant Icacinaceae leaf morphology. Leaves of Icacinaceae are simple, usually borne in spiral arrangement, but opposite phyllotaxy occurs in a few genera including

Cassinopsis Sond., Iodes, and Mappianthus. Most genera have unlobed elliptical leaves

(although there are some ovate and occasionally obovate species); however, some species of

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Phytocrene and Pyrenacantha (e.g., Pyrenacantha lobata (Pierre) Byng & Utteridge, Byng et al.,

2014) are palmately lobed. Icacinaceous leaves typically have untoothed margins but are rarely minutely toothed (e.g., Natsiatopsis Kurz, Hosiea, Kårehed, 2001). When teeth are present, they are usually nonglandular, enervated by minor veins that extend to, or slightly beyond, the margin. Primary venation is usually pinnate, but is palmate in a few genera (e.g., Natsiatopsis,

Natsiatum, Phytocrene, Pyrenacantha, Kårehed, 2001). The secondary veins are typically brochidodromous. Tertiaries and higher order venation are generally regular and well organized across the family (Fig. 5-11).

We reviewed herbarium specimens of extant Iodes species and found many features are consistent with the fossils. From the specimens examined (Table 5-2), most species are notophyllous to mesophyllous in size, while Iodes liberica Stapf (MO 05005469) is microphyllous. Length to width ratios included the range observed in the fossils, but there are also examples with more slender leaves such as Iodes velutina King (MO 4018700) whose ratio is consistently over 2.0:1. Shape is usually elliptic with a few specimens that are slightly basally or medially asymmetrical. Apex angle and shape are more variable in the extant species; some have an obtuse angle and convex, obtuse, or emarginate shape, while many others share a generally acute apex with the fossil species. Base shape of extant Iodes varies from acute to obtuse to reflex with overall laminar shape varying accordingly. The fossils also seem to show signs of pubescence, which is consistent with leaves of extant Iodes.

All extant Iodes examined have pinnate primary venation. Basal veins are usually naked

(forming the leaf margin) and vary from one to seven. Secondary veins are festooned brochidodromous with no intersecondary veins. The spacing between adjacent secondary veins usually decreases proximally, while the angle of divergence of secondaries from the midvein

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increases smoothly or abruptly as seen on the fossils. Secondaries have an excurrent attachment to the midvein, while tertiaries are opposite to rarely alternate percurrent. Tertiary vein angle varies from relatively consistent to basally concentric, while epimedial tertiaries are opposite percurrent. Exterior tertiaries are looped; fourth and fifth order venation is reticulate. Areoles are present with moderate to good development and branched freely ending veinlets that are often obscured by excessive pubescence especially on the abaxial leaf surface. Marginal ultimate venation is looped (Fig. 5-11).

Iodes scandens (Becc.) Utteridge & Byng (previously in its own genus, Polyporandra) also has morphological similarities to the Blue Rim specimens. We examined two herbarium specimens of I. scandens (MO 3487929 and MO 6178926) for comparison with the fossils. The specimens had a relatively long length to width ratio of up to 2.49:1. Leaves were elliptic and symmetrical with acute acuminate apices and acute slightly convex to convex bases. Secondaries were slightly different than the fossil specimens in that they were eucamptodromous becoming brochidodromous distally. The higher order venation was comparable with other species of

Iodes.

Goweria bluerimensis is known only from isolated leaves, and the source twigs are unknown, so the arrangement and organization, whether opposite as in extant Iodes (and its sister genus, Mappianthus) or alternate as in most other genera of the family, cannot be determined. If these leaves do indeed belong to Iodes, we can hypothesize that the leaves of this extinct taxon were opposite. The petiole preservation suggests it has a resistant strand of vascular tissue preserved in the center. This feature seems taxonomically significant because the petioles of other angiosperm leaves preserved in the same sediments at Blue Rim do not show such a distinct central dark band. When we examined the petiole of an Iodes ovalis Blume herbarium

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specimen (MO 4255558) with focused transmitted light we observed a single, dark, vascular trace running the length of the petiole. A vascular strand is also visible in the petiole of the cleared leaf of Iodes trichocarpa Mild. (see Fig. 5-11C). Icacinaceae s.s. (except for Cassinopsis) have a single vascular strand leading to each leaf, but it is not known if expanded petioles with a narrow, resistant vascular strand are found across the family. As the arrangement and number of vascular strands within petioles varies across families and genera (figs. 9.1-9.5 in Howard, 1979 illustrate a classification of the vasculature of non-monocot petioles), we consider this feature to be informative for the recognition of leaves of Icacinaceae. The mucronate-like projection at the apex of well-preserved specimens (e.g., Fig. 5-10A) corresponds to a projection of the midvein past the laminar tissue on the apex of many extant Iodes taxa, but this feature is also found in other genera of Icacinaceae.

Comparison with other leaf fossils. Goweria bluerimensis sp. nov. has been found at several localities at Blue Rim, but so far has not been observed in other fossil floras. Fossil leaves from other Eocene localities including the Green River (WY, UT, CO), Yellowstone-

Absaroka (WY), and Clarno (OR) were examined to see whether any corresponded with the Blue

Rim material. MacGinitie (1969) documented three leaves from the Green River flora that look superficially similar to G. bluerimensis. Aristolochia mortua Cockerell has a similar overall shape and looping secondary venation, but differs in both the number of primary basal veins and tertiaries. Erythrina roanensis MacGinitie shares a thick petiole and looping secondaries with G. bluerimensis, but has an emarginate apex and a different pattern of higher order venation.

Aleurites glandulosa (Brown) MacGinitie has an acute apex, looping venation, and ladder-like percurrent tertiaries, but has an acute base and three strong basal veins that were not seen on G. bluerimensis. Furthermore, MacGinitie (1974) noted three other taxa from his Yellowstone-

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Absaroka flora that could be initially mistaken for G. bluerimensis. Aristolochia solitaria

MacGinitie shares a similar overall shape and looping venation, but contrasts with its three strong basal veins and very polygonal reticulate higher order venation. Canavalia diuturna

MacGinitie is pinnate with looping venation with secondaries diverging at a higher angle near the leaf base. The overall shape is similar to G. bluerimensis, but the tertiary venation is more reticulate and the petiole is slender. Finally, Luehea newberryana (Knowlton) MacGinitie displays some looping venation and distinct opposite percurrent tertiaries that are perpendicular to the midrib, but differs in having multiple strong basal veins and having teeth. No specimens from the Clarno Formation (OR) have leaf architecture that matches with G. bluerimensis.

Comparison with other Icacinaceae leaf fossils. Fossil leaves previously assigned to

Icacinaceae are rare, perhaps due in part to the difficulty in finding diagnostic characters, i.e., features that are not also present in other plant families. In North America, the middle Eocene

Chalk Bluffs flora preserves leaves from near You Bet, CA, in the Sierra Nevada Mountains, assigned to Phytocrene sordida (Lesquereux) MacGinitie (1941). One of MacGinitie’s Chalk

Bluffs species, Ficus densifolia Knowlton, was later transferred to Icacinaceae as Miquelia californica Wolfe (1977). Wolfe (1968) initially placed Goweria in Menispermaceae, but later

(Wolfe, 1977) reassigned it to Icacinaceae. Many of the characters in Wolfe’s diagnosis of

Goweria apply to the leaves presented here including the ovate shape, multiple basal veins, straight secondaries that loop near the margin, percurrent tertiaries that loop near the margin, a thick petiole, and reticulate higher order venation. Wolfe (1968) described the primary venation of Goweria as palmate with five primaries, many of these only extending halfway to the apex. In examining the specimens Wolfe assigned to Goweria and taking into account the changes in standard leaf terminology since 1968 (other basal veins are at least 75% of the thickness of the

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midvein to be considered primaries, Ellis et al., 2009), we assigned these fossils to Goweria.

There are no characters in Wolfe’s (1968) diagnosis of the genus that preclude the assignment of the Blue Rim species to this genus as G. bluerimensis. However, in 1977, when Wolfe transferred Goweria to Icacinaceae, he emended his initial diagnosis of this genus from having a marginal vein to just a thickened margin. Goweria bluerimensis has a marginal secondary vein.

Sometimes it is obscured and seems to diminish toward the apex, but it is always present near the base. Wolfe (1968, 1977) described three species of Goweria: G. dilleri, G. lineraris, and G. alaskana. Both G. dilleri and G. lineraris are described as having common intersecondary veins, which are not present in G. bluerimensis. The presence or absence of intersecondaries was not mentioned in the description of G. alaskana but was not observed on the type specimen. Wolfe

(1977) also described leaves of Phytocrene acutissima Wolfe, Phytocrene sordida, and

Pyrenacantha sp. While many of the characters of Wolfe’s Phytocrene species, including the ovate shape, rounded to cordate base, and acuminate apex, align with G. bluerimensis, the leaves have small, irregular teeth, which are not seen on any of the Blue Rim specimens.

Other leaves assigned to Icacinaceae include five species in five genera from the middle

Eocene of Hokkaido, Japan (Tanai, 1990). The taxa assigned to Icacinaceae from this locality include Goweria bibaiensis Tanai, Huziokaea eoutilus (Endo) Tanai, Merrilliodendron ezoanum

Tanai, Phytocrene ozakii Tanai, and Pyrenacantha sp. Goweria bibaiensis shares some features with G. bluerimensis, including a similar size and frequent ovate shape. Tanai (1990) noted that

G. bibaiensis is palmately veined with five primary veins, camptodromous secondaries, and the marginal tertiaries terminate in small bumps. In contrast, G. bluerimensis has an untoothed margin, brochidodromous secondaries, and is pinnate with five or more basal veins (it is possible that Tanai interpreted some of the basal veins as primaries). Assessing whether these other

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previously published fossil leaf occurrences still fall within our current understanding of

Icacinaceae is outside the scope of this paper. Although the genus Icaciniphyllum was established for fossil leaves from the Paleogene of Europe once thought to represent Icacinaceae

(Kvaček and Bužek, 1995), the type species was later recognized as Sloanea L. (Elaeocarpaceae;

Kvaček et al., 2001), so the genus Icaciniphyllum is not available for icacinaceous fossils.

Paleoecological implications. Broadleaved evergreen leaves tend to be thicker than broadleaved deciduous leaves (Chaloner and Creber, 1990). Leaf thickness is difficult to estimate directly from fossil leaf impressions, but the positive correlation between petiole thickness and laminar thickness (quantified as mass per area) documented in modern angiosperm leaves allows for estimation of leaf thickness when petioles are preserved (Royer et al., 2007). A leaf mass per area (MA) analysis was completed on the specimens of Goweria bluerimensis with intact petioles following the methods outlined by Royer et al. (2007). Petiole width (PW) and leaf area (A) were measured in millimeters and squared millimeters, respectively, using ImageJ. There were 19 G. bluerimensis specimens with an intact petiole near the base of the leaf. The resulting MA using

2 the formula from Royer et al. (log[MA] = 3.070 + 0.382 x log[PW /A], Royer et al., 2007) was

2 119.45 g/m . In a more conservative approach, MA was recalculated using only those specimens where most of the leaf was intact (therefore excluding the specimens where more than 1/3 of the leaf area had to be estimated with ImageJ). This calculation was completed with 11 specimens

2 2 for an MA of 109.09 g/m . Both of these numbers fall within the range of 87 to 129 g/m , which suggests the fossil G. bluerimensis leaves had an approximately 1 year lifespan and were likely

2 2 deciduous. An MA of <87 g/m suggests a leaf lifespan under 1 year, while an MA of >129 g/m indicates a lifespan greater than 1 year (Royer et al., 2007). It is important to note that the petioles on the fossils may be slightly wider due to taphonomic alteration (Royer et al., 2007).

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Therefore, these estimates for MA on the fossil G. bluerimensis are likely slightly higher than they would be if fresh material were measured. However, leaf lifespan would likely still be in the range of 1 year.

This estimate of MA for G. bluerimensis can be compared with other Eocene fossil floras

2 2 in North America. MA averaged 76.8 g/m with a range of 57 to 87 g/m for the Republic fossil flora (WA) in the Klondike Mountain Formation (~49 Ma, Royer et al., 2007). These estimates of this lacustrine flora suggest leaf lifespans under 12 months. These leaves also showed high levels of herbivory. A different fossil lake flora preserved in the Green River Formation of

2 2 Bonanza, UT (~47 Ma), had a mean MA of 113.2 g/m with a range from 70 to 157 g/m (Royer et al., 2007). This flora’s higher leaf mass per area suggests more taxa with longer living leaves and generally different ecological strategies. The Bonanza site had correspondingly less herbivory than the Republic site (Royer et al., 2007). The estimate of MA using G. bluerimensis is in the middle of these two floras. However, estimating the MA from multiple species at Blue

Rim (rather than just one) is warranted for a more accurate comparison.

Despite these results, the applicability of estimating MA using fossil leaves from vine or liana taxa has not been examined in detail. The original data set used by Royer et al. (2007) to create the formula to estimate MA from fossil leaves contained only ~12 taxa with a vine habit of the 667 species-site pairs. Studies on modern forests have shown that lianas tend to have both a lower leaf mass per area and leaf lifespan than trees growing in the same location (Wright et al.,

2004; Cai et al., 2009; Zhu and Cao, 2010; Kazda, 2015). Furthermore, unless a confident taxonomic assignment has been applied to a fossil leaf morphotype, as was done with Goweria bluerimensis, the habit (e.g., tree, vine, shrub) of the original plant is usually not known.

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In addition, a few fossil specimens of G. bluerimensis (notably UF 19338-58273, UF

15761N-57274, and UF 19225-56970) had larger circular structures randomly arranged across the leaf surface. Initial interpretation suggested that these marks were small galls, but upon closer inspection they are more closely aligned with fungal damage (E. Currano, University of

Wyoming, personal communication, May 2013).

Final remarks on G. bluerimensis. While many of the characters of Goweria bluerimensis seem convergent with those of other tropical eudicot families, the co-occurrence of these leaves and the fruits of Iodes occidentalis at several sites along the Blue Rim escarpment provided strong evidence for assignment to Icacinaceae. If the hypothesis that the G. bluerimensis leaves were produced by the same species as the Iodes occidentalis fruits is correct, then these leaves would belong to the extant genus Iodes. However, by themselves, the leaves do not provide sufficient characters for definitive placement in this modern genus, particularly in view of the fact that a related, but extinct, icacinaceous fruit type, Biceratocarpum brownii, also occurs at Blue Rim. Specimens of B. brownii are rare at Blue Rim, but their presence argues for caution in assumptions about co-occurring organs especially since there are shared morphological features among the leaves of different genera in Icacinaceae.

Discussion

Overview of Icacinaceae Fossil Record

Paleobotanists have typically placed fossil fruits of Icacinaceae into either the Iodeae or

Phytocreneae based on the general fruit characters displayed by these two tribes (e.g., Reid and

Chandler, 1933; Pigg et al., 2008; Rankin et al., 2008). Genera of the Phytocreneae—Miquelia,

Phytocrene, Pyrenacantha (including Chlamydocarya Baill. and Polycephalium Engl.; Byng et al., 2014), and Stachyanthus Engl.—for example, have endocarps with pitted surfaces, generally corresponding to tuberculate protrusions into the locule. The size and spacing of the pits, as well

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as the morphology of the tubercles, are potentially diagnostic for particular genera within the tribe. Fossil fruits of the Phytocreneae are known primarily from the Paleogene of North

America (e.g., Manchester, 1994; Rankin et al., 2008; Stull et al., 2012) and Europe (e.g., Reid and Chandler, 1933; Collinson et al., 2012), although records are also known from the Paleocene of South America (Stull et al., 2012) and the Oligocene of Africa (Manchester and Tiffney,

1993).

Genera of the Iodeae (as traditionally circumscribed, including Hosiea, Iodes,

Mappianthus, Natsiatum, and Polyporandra) have bivalved endocarps encircled by a keel in the plane of bisymmetry (within which, or upon which, the main vascular bundle runs, along one side of the endocarp). The keel terminates in an asymmetrical apical bulge (marking the entrance of the vascular bundle into the endocarp to supply the ovules). The endocarp surface bears a prominent reticulum of ridges. Fossil fruits attributed to the Iodeae have been described from numerous localities ranging from the late Cretaceous (Knobloch and Mai, 1986) to the Oligocene

(Kvaček and Bužek, 1995), with the majority being from the Paleogene of North America (e.g.,

Manchester, 1994; Pigg et al., 2008; Stull et al., 2011) and Europe (Reid and Chandler, 1933;

Collinson et al., 2012). However, the attribution of fossil fruits to the Iodeae tribe is now seen to be highly problematic. Some of the fruit features considered characteristic of the tribe are not unique to it. For example, the reticulately ridged endocarp surfaces and asymmetrical apical bulges also occur in some genera of the traditional Icacineae tribe (e.g., Alsodeiopsis,

Desmostachys, Rhyticaryum). In addition, phylogenetic analyses show that the Iodeae, in their traditional circumscription, are polyphyletic (Byng et al., 2014; Stull et al., in prep.). Additional phylogenetic and morphological work is necessary to ascertain fruit characters useful for

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diagnosing broader clades within the family—particularly among genera of the traditional Iodeae and Icacineae.

However, among the traditional Iodeae genera, Iodes, a Paleotropical genus containing

~16 spp., appears monophyletic (Byng et al., 2014) and clearly diagnosable based on morphological grounds. In fruits of Iodes, the main vascular bundle (which runs from the base of the fruit to the apex) is embedded within the endocarp wall; in all other Iodeae and “Iodeae”-like fruits of the Icacineae, the vascular bundle runs outside the endocarp wall, through the mesocarp.

In addition, many species of Iodes also bear papillae on the inner endocarp surface, which is a rare character among other icacinaceous genera. These characters, when sufficiently preserved, may allow confident identification of Iodes in the fossil record.

Iodes Fossil Record

Fossils fruits of Iodes, representing three taxa (I. multireticulata, “I.” corniculata Reid &

Chandler, and I. eocenica Reid & Chandler), have been described from the early Eocene London

Clay flora (Reid and Chandler, 1933). These fossils were noted to display considerable similarity in particular with African species of Iodes (e.g., I. africana Welw. ex Oliv.). One of these fossil species, I. multireticulata, has also been documented from the early Eocene Fisher/Sullivan site of Virginia (Tiffney, 1999) and the middle Eocene Clarno Nut Beds of Oregon (Manchester,

1994), from which an additional species of Iodes, I. chandlerae Manchester, was also described.

In addition to these four species, several other fossil species have been placed in extinct genera that may represent Iodes or closely related stem taxa. Croomiocarpon mississippiensis Stull,

Manchester et Moore shows a prominent reticulum of ridges as well as a vascular bundle embedded within the endocarp wall (Stull et al., 2011), suggesting affinities with Iodes.

Although this fossil lacks papillae on its inner endocarp surface, papillae are also apparently absent from several extant species of Iodes. Additionally, this species has a cleft at the base of 383

the endocarp similar to multiple extant Asian species of Iodes (e.g., I. cirrhosa, I. seguinii).

Iodicarpa Manchester also has an embedded vascular bundle and papillate inner endocarp surfaces (Manchester, 1994), suggesting affinities with Iodes, with the main difference apparently being the much larger size of Iodicarpa (length 26–56 mm, width 20–35 mm, endocarp wall thickness 2–4 mm), although several Asian species of Iodes have relatively large fruits (e.g., endocarps of Iodes balansae Gagnepain are up to 38 mm in length; Hua and Howard,

2008).

Finally, Palaeohosiea might also represent the extant genus Iodes. Palaeohosiea (Kvaček and Bužek, 1995) includes three species: P. suleticensis Kvaček & Bůžek, P. bilinica

(Ettingshausen) Kvaček & Bůžek, and P. marchiaca (Mai) Kvaček & Bůžek. The genus is similar to Iodes in having keeled endocarps covered with a reticulum of ridges, with a papillate lining on the inner endocarp surface, and a vascular bundle that enters the endocarp at the base and runs in the keeled margin toward the apex. The similarity between Palaeohosiea and Iodes was noted by Kvaček and Bůžek (1995), but they distinguished Palaeohosiea from the modern genus based on the prominent keel found in Palaeohosiea, which they deemed absent from

Iodes. However, prominent marginal keels are in fact present on practically all extant species of

Iodes (e.g., Fig. 5-1). Kvaček and Bůžek also distinguished Palaeohosiea from Iodes and other known genera of Icacinaceae based on the foliage associated with the fossils, which they interpreted as icacinaceous but distinct from known genera. However, these fossil leaves have since been recognized to represent a separate family, Elaeocarpaceae (Kvaček et al., 2001).

Therefore, no major characters distinguish Palaeohosiea from Iodes. These three taxa—one of which, P. bilinica, was also documented at Messel, alongside a possible new species, informally

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described as Palaeohosiea sp. (Collinson et al., 2012)—possibly should be transferred to the genus Iodes unless other distinguishing characters can be identified.

Iodes occidentalis is distinct from previously described fossils in its overall shape

(globose vs. more lenticular in the other species of Iodes) and in its endocarp reticulation pattern

(it has more frequent freely ending ridgelets). “Iodes” corniculata, which has rare freely ending ridgelets, also possesses a pair of subapical horn-like protrusions (discussed more below), distinguishing it from I. occidentalis. Collectively, however, these fossils are perhaps more similar to fruits of modern African species than fruits of modern Asian species. The African species tend to have smaller, more globose endocarps with a denser reticulation including relatively frequent freely ending ridgelets. These features contrast with those of the Asian ones, which typically have much larger fruits, lenticular in cross section, with a more diffuse reticulation pattern, and often, an asymmetrical cleft near the base of the fruit.

Iodes Biogeography

Iodes is presently confined to rainforests of Africa, Madagascar, and Indo-Malesia (Fig.

5-12). However, based on the fossil record described here, the genus had a much broader historical distribution during the Eocene, when thermophilic forests extended well into the

Northern Hemisphere (Tiffney, 1985). This fossil record suggests that the Northern Hemisphere may have played an important role in the diversification and global spread of Iodes across the tropics. Reid and Chandler (1933) noted the close similarity of I. multireticulata with modern species from Africa, especially I. africana. Iodes occidentalis is also more morphologically similar to fruits of African species (Fig. 5-1). Croomiocarpon mississippiensis, however, is considerably larger and possesses a cleft at the base of the endocarp, similar to modern species in

Asia. The presence of fruit morphologies similar to both extant Asian and African species in the

Eocene of the northern hemisphere provides even more clear evidence that the high-latitude 385

thermophilic forests present during the Paleogene played an important role in the early evolution of this genus. The shared presence of I. multireticulata in Europe and North America during the early–middle Eocene suggests that the North Atlantic Land Bridge (NALB) facilitated migration between these regions (Reid and Chandler, 1933; Manchester, 1994). However, while the northern hemisphere seemed to play an important role in the early evolution of the genus, its place of origin remains uncertain. The oldest records are from the early Eocene of Europe and

North America (Reid and Chandler, 1933; Tiffney, 1999; this paper), but the Paleogene fossil record of Africa and Asia, where the genus occurs today, is more poorly known, especially based on well-preserved fruit and seed fossils (Jacobs, 2004). Thus, the absence of older records from

Africa/Asia might represent a sampling artifact. However, older fossils of the family in general are known from North America (Paleocene: Pigg et al., 2008; Stull et al., 2012) and Europe

(Maastrichtian: Knobloch and Mai, 1986), suggesting that the family itself might have originated in the Northern Hemisphere.

Systematic and Biogeographic Significance of Biceratocarpum

Although Biceratocarpum brownii is similar to Iodes in several important respects

(embedded vascular bundle, papillate inner endocarp surfaces), it is distinctive in having a subapical pair of horns and in having a closed reticulum of ridges lacking freely ending ridgelets.

The former feature—the pair of horns—is particularly distinctive and not known in another extant genus of Icacinaceae. The similarities with Iodes suggest a close relationship, but the differences suggest that this taxon might fall outside the Iodes crown group. We therefore placed this species in a new genus to reflect its morphological distinctness (and perhaps phylogenetic isolation). Interestingly, the London Clay species “Iodes” corniculata also displays a pair of subapical horns (Reid and Chandler, 1933). Work is currently in progress on revising the systematics of Icacinaceae from the London Clay flora (G. W. Stull et al., unpublished 386

manuscript) and will likely involve the transfer of “I.” corniculata to Biceratocarpum.

Furthermore, given the morphological similarity of the London Clay fossils with B. brownii, these fossils may be conspecific, in which case the older name (brownii) would take priority (as

Biceratocarpum brownii) and encompass both the London Clay and western North American fossils.

The disjunction of B. brownii and “I.” corniculata (given their putative close relationship) is possibly the result of migration across the NALB, which seems to have served an important role in facilitating the migration of tropical taxa between North America and Europe during the early Eocene (Tiffney, 1985). The pattern of one species or two closely related species disjunct between North America and Europe during the Eocene is relatively common

(Manchester, 1999), and B. brownii and “I.” corniculata thus provide another piece of evidence supporting the Eocene biogeographic connection of North America and Europe, presumably facilitated by the NALB. Biceratocarpum (and “I.” corniculata) also further highlight the importance of the Northern Hemisphere in the early diversification of the family.

Biceratocarpum appears to have represented a distinctive lineage within the family, with a relatively wide distribution (North America and Europe), that presumably went extinct due to climate deterioration during the late Eocene–Oligocene.

Overview of Icacinicarya and Icacinicaryites

Both Icacinicarya and Icacinicaryites function as repositories for icacinaceous fossils of uncertain generic placement, although the former is reserved for anatomically preserved specimens and the latter for compression/impression material. Over 20 species of Icacinicarya have been described, ranging from Maastrichtian to Eocene in age (reviewed in Pigg et al.,

2008). Two species of Icacinicaryites have been previously described from the late Paleocene of western North America (Pigg et al., 2008). Icacinicaryites lottii, described here, is considerably 387

smaller than the two previously described Icacinicaryites species [I. linchensis Pigg, Manchester,

& DeVore and I. corruga (Brown) Pigg, Manchester, & DeVore]; it also appears to have smaller, more regularly sized areoles in the endocarp reticulation. The broad stipe of I. lottii is also distinctive, but the absence of similar structures on the other species of Icacinicaryites could be an artifact of preservation. Since Icacinicarya and Icacinicaryites do not necessarily represent natural/monophyletic groups (but rather repositories for fossils of Icacinaceae of uncertain generic placement), it is not really reasonable to draw any biogeographic conclusions for these genera as a whole based on the distributions of their constituent fossil taxa.

Paleoecological Implications

We discuss the paleoecology of these taxa in relation to the Blue Rim flora. This locality has been the most extensively studied of the sites discussed here and has both Iodes fruits and associated leaves preserved.

Many Icacinaceae taxa, including Iodes, are lianas (Kårehed, 2001). Today, lianas, which have a very large leaf mass for their stem diameter, account for a quarter of woody stems in lowland tropical forests (Putz and Chai, 1987; Gentry, 1991; Andrade et al., 2005; Schnitzer,

2005). Lianas are more common in areas with marked seasonality (longer dry seasons) and less common in areas with high mean annual rainfall (Schnitzer, 2005; DeWalt et al., 2010; DeWalt et al., 2015). In addition, most lianas are found in tropical latitudes as their anatomy of both wide and long water vessels makes them very susceptible to freezing and harmful embolisms (Gentry,

1991; Schnitzer, 2005). However, this anatomy enables them to efficiently transport water to their extensive crown even with a narrow stem. Lianas take advantage of deep and extensive root systems to survive during the dry season (Andrade et al., 2005; Schnitzer, 2005).

The leaf mass per area (MA) calculation suggested that the Goweria bluerimensis leaves at the Blue Rim site have a lifespan of approximately 1 year and were likely deciduous. This 388

aspect is discussed in more detail in the discussion in the previous systematics section. However, it is important to note that most modern species of Icacinaceae tend to occur in predominately evergreen rather than deciduous forests. The estimate that Goweria bluerimensis is deciduous may relate to the fact that lianas tend to drop their lower leaves as the canopy closes (Rowe et al.,

2004). Furthermore, deciduous lianas are most likely to lose their leaves during the driest time of the year, but lianas are often more resistant to seasonal dryness than the tree species they are growing on (Kalácska et al., 2005; Schnitzer and Bongers, 2011).

There is little literature on the ecology of extant Icacinaceae. In a study of all taxa with a liana habit in Lambir National Park, Sarawak, Malaysia, three species of Icacinaceae lianas including Iodes were documented (Putz and Chai, 1987). After Fabaceae, Icacinaceae had the most individual lianas in this forest survey. In addition, Putz and Chai (1987) found that liana taxa were more common in valley rather than ridge plots. The high prevalence of Iodes endocarps in addition to associated leaves at the Blue Rim site suggests this was a common taxon in that area. If Iodes had similar ecological preferences in the Eocene of Wyoming as compared with Southeast Asia today, this site likely represents a lowland. This inference is corroborated by the fluvial depositional environment at Blue Rim. Many of the other taxa preserved at the Blue

Rim site, including Populus L. (Salicaceae) and Acrostichum L. (Pteridaceae), support the interpretation of an environment with high soil moisture or nearby water bodies.

Icacina oliviformis (Poir.) J. Raynal, an extant species in a different clade of the family, has been extensively studied. The fruits (the mesocarp only) of this taxon were observed as a food source for both baboons and monkeys in northern Central African Republic (Fay, 1993).

Primate fossils are present in other parts of the Bridger Formation (e.g., Gunnell, 1998). It is inferred that primates in the Eocene also lived in forested environments like primates today and

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likely ate icacinaceous taxa. Iodes and other taxa (e.g., Lygodium kaulfussi and Vitis L.) inferred to be climbers at Blue Rim based on nearest living relatives are also strong indicators that this area was at least partially forested as vines and lianas rely on trees for support.

In sum, the presence of Icacinaceae in the Blue Rim flora, specifically their liana habit, suggests a low chance of frost and a multistratified forest structure in a local or regional lowland.

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Table 5-1. List of herbarium specimens examined for fruit comparative work. Herbarium code “MO” = Missouri Botanical Garden, St. Louis, Missouri, USA. Taxon Voucher Locality Country Year Herbarium Sheet Number Iodes africana Breteler, Lemmens, between Gabon 1987 MO Welw. ex Oliv. Nzabi 8231 Mouila and 4314613 Yeno Iodes klaineana de Wilde et al. 606 SE of Gabon 1986 MO Pierre Tchibanga 4302002 Iodes ovalis Hiep et al. HLF203 Na Hang Vietnam 2002 MO Blume Nature Reserve 6243998 Iodes ovalis Lau 148 Ngai District, China 1932 MO Blume Hainan 1098159 Iodes perrier Jongkind 3696 Toliara Madagascar 1997 MO Sleumer 6243553 Iodes seretii Ekwuno, Fagbemi, Edondon Forest Nigeria 1978 MO (DeWild) and Osanyinlusi Res. 2730593 Boutique PFO.370 Iodes Luke 10774 Tana River Kenya 2004 MO usambarensis District 5989989 Sleumer Polyporandra Takeuchi 9320 Morobe Paupa New 1994 MO scandens Becc. Province, Guinea 6178926 Atzera Range

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Table 5-2. List of herbarium specimens examined for leaf comparative work. Herbarium code “MO” = Missouri Botanical Garden, St. Louis, Missouri, USA. Taxon Voucher Locality Country Year Herbarium Sheet Number Icacinaceae (likely Zhanhuo 91- Jinghon Xian, S. China 1991 MO 4255558 Iodes cirrhosa 324 Yunnan Turcz.) Iodes africana Carvalho Bata-Senge Equatorial 1994 MO 5165184 Welw. ex Oliv. 5626 Guinea Iodes kamerunensis Bos 5170 31 km from Cameroon 1969 MO 5660279 Engl. Kribi, Lolodorf Road Iodes klaineana de Wilde et SE of Tchibanga Gabon 1986 MO 4302002 Pierre al. 606 Iodes liberica Staph Jongkind and outside Ankasa Ghana 1995 MO 05005469 Abbiw 2177 Game Reserve Iodes velutina King Maxwell 82- Botanic Gardens Singapore 1982 MO 4018700 var. velutina 30 “Jungle” Polyporandra Takeuchi Morobe Paupa New 1994 MO 6178926 scandens Becc. 9320 Province, Atzera Guinea Range Polyporandra Van Balgooy NW Buru, Indonesia 1984 MO 3487929 scandens Becc. 5060 Maluku Islands

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Figure 5-1. Extant Iodes fruits for comparison with the fossil specimens. (A–D) Iodes klaineana Pierre, Wilde 606 from Gabon. A) Lateral view showing reticulum of ridges and pubescence. B) Dorsal view showing prominent keel. C) Apical view with remnant stigma. D) Basal view with persistent calyx. (E, F) Iodes cf. madagascariensis Baill, McPherson 18809 from Madagascar. E) Lateral view with reticulum of ridges. Keel is visible on the left side of the fruit. F) Dorsal view showing prominent keel. G) Iodes klaineana Pierre, A. Leonard 154, from Yangambi, Congo, showing prominent vascular bundle within endocarp (arrow). H) Iodes africana Welw. ex Oliv., Breteler et al., 8231, x-ray section, transverse through the apical 1/4 of the fruit. Vascular bundle within the endocarp indicated with an arrow. Scale bar = 1 mm. I) Natsiatum herpeticum Buch.-Ham. ex Arn., A.J.C. Grierson & D. G. Long 3775, Bhutan. Cross section with arrow indicating vascular bundle in mesocarp rather than endocarp. Scale bars = 5 mm (all except H).

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Figure 5-2. Map showing the fossil localities referenced in the text. Relevant Icacinaceae specimens have been found at the Clarno Nut Beds (NB) locality in Oregon; Kisinger Lakes (KL), Tipperary (TP), Blue Rim (BR), and Barrel Springs (BS) localities in Wyoming; Bonanza, Utah (BZ); and Douglas Pass, Colorado (DP). Base map generated and sites plotted via Map-it (http://woodshole.er.usgs.gov/mapit/).

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Figure 5-3. Fruits of Biceratocarpum brownii gen. et comb. nov. (A, B) Two counterpart halves of an endocarp mold from the Clarno Nut Beds, Oregon, UF 00225-9902. A) Blue arrow highlights an infilling of the bottom portion of the vascular canal, which presumably ran within the endocarp wall from the base to the apex, where it entered the locule to supply the ovules. B) Blue arrows highlight the subapical horns. C) Impression specimen of this species from Blue Rim, Wyoming, UF 19225-54569. D) Lectotype, designated here, of Biceratocarpum brownii, comb. nov., USNM 316745a from Tipperary, Wyoming. Note the horn toward the apex of the fruit and the absence of freely ending ridges penetrating the areoles on this mold of the endocarp surface. E) A second specimen, a locule cast, from the same hand sample as the Lectotype, USNM 316745b. F) Endocarp impression with shadowed protrusion of horn into the sediment indicated by arrow. From the Parachute Creek Member of the Green River Formation, Colorado, USNM 57250 (USNM loc. 41142). G) Impression of endocarp with horn indicated by arrow, Kisinger Lakes flora, UF 19376-59511. Scale bars = 5 mm.

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Figure 5-4. Papillae of fossil and modern specimens of Icacinaceae. (A–C) Close up of papillae impressions on the surface of locule casts. A) Biceratocarpum brownii gen. et comb. nov., USNM 316745. B) Iodes occidentalis sp. nov., UF 15761-22704. C) Iodes occidentalis sp. nov., UF 19225-57243. D) Papillae of extant Iodes cf. madagascarensis Baill., McPherson 18809, for comparison. Scale bars = 0.25 mm.

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Figure 5-5. Drawing of Biceratocarpum brownii gen. et comb. nov. emphasizing features observed on fossils and described in text. A) Lateral view. B) Dorsal view.

Figure 5-6. Phytocrene blancoi (Blanco) Merr., Elmer 15960, Luzon Island, Philippines, MO 833710. A) Lateral view with arrow showing apical channel in the endocarp. B) Side view with both apical channels indicated by arrows. Scale bars = 5 mm.

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Figure 5-7. Icacinicaryites lottii sp. nov. fruits from the Kisinger Lakes flora of Wyoming. A) Well-preserved endocarp and subtending stalk impression, UF 19376-59514. Freely ending ridges (preserved as furrows) are present in the majority of the fruit’s areoles. B) Impression, UF 19376-59515. C) Counterpart to B; UF 19376-59515’. Scale bars = 5 mm.

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Figure 5-8. Selection of Iodes occidentalis sp. nov. fruits from the Blue Rim flora (Bridger Formation) in southwestern Wyoming showing notable characteristics. These are impressions unless otherwise indicated. A) UF 19225-51993. B) UF 19225-51996. C) UF 15761-22683. D) Specimen (cast) showing an infilling of the vascular bundle (arrow) positioned within the space left by endocarp wall, UF 19225-57242. E) Close up of the cast in D. Scale bar = 2.5 mm. F) Fruit with rare pedicel, UF 19225-57241. G) Ridge impressions of the endocarp visible on the locule cast. This locule cast also shows numerous small, densely spaced holes (more greatly enlarged in 5-4C), which are impressions of the papillae originally lining the inner endocarp surface of the fruit, UF 19225-57243’. Scale bar = 2.5 mm. H) Impression counterpart of the endocarp in G. These are shown at the same magnification to show the relative endocarp wall thickness, UF 19225-57243. Scale bar = 2.5 mm. I) Common preservation of fruits at Blue Rim, UF 19225-51997. Scale bars = 5 mm (except E, G, and H: scale bars = 2.5 mm as noted).

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Figure 5-9. Impressions of fruits of Iodes occidentalis sp. nov. from the Barrel Springs locality (Green River Formation) in Wyoming (A–C) and the Douglas Pass Radar Site II locality in Colorado (D). A) UF 18151-62097. B) UF 19335-56837. C) UF 19335- 56836. D) UF 00582-57564. Scale bars = 5 mm.

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Figure 5-10. Selection of leaves of Goweria bluerimensis sp. nov. from the Blue Rim flora (Bridger Formation) in southwestern Wyoming. A) Composite image of the part and counterpart of UF 15761N-57228. Apical protuberance and vascular strand in the petiole are visible. B) Cordate base and looping secondary venation are visible, UF 19225-51975. C) Note overall cordate shape, UF 15761-55239. D) Ladder-like tertiaries, UF 15761-55241. E) Unusual rounded shape, UF 19225-57111. F) Intact acute apex, UF 15761-55240. G) Leaf fragment adjacent to fruit of Iodes occidentalis sp. nov., UF 19337-57978’. H) One of the smallest leaves of Goweria bluerimensis, UF 15761N-57271’. I) Clear vascular strand in the petiole, UF 15761S-57861. Scale bars = 10 mm.

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Figure 5-11. Extant Iodes leaves for comparison with the fossil specimens. Each specimen is identified with its name and authority, collector, locality, and herbarium if available. Original slides are part of the National Cleared Leaf Collection housed at the Smithsonian Museum of Natural History in Washington, D.C. A) Iodes philippinensis Merr. (det. Sleumer), M. S. Clemens 32172, Mt. Kinabalu, Brit. N. Borneo, Leiden. Arrows indicate areas where the original slide mounting medium has discolored, partially obscuring the leaf. B) Iodes reticulata King., Yates 1342, Sumatra, USNH 1551286. Arrow indicates area where the original slide mounting medium has discolored, partially obscuring the leaf. C) Iodes trichocarpa Mild., Linder 1886, unknown, Arnold Arboretum. The single vascular bundle in the petiole is visible as a dark line (arrow). D) Iodes seguini (Léul.) Rehd. (det. Sleumer), Liang 69753, Kwangsi, Arnold Arboretum. Scale bars = 10 mm.

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Figure 5-12. Modern distribution of Iodes in central Africa, Madagascar, southeastern Asia, and the central Indo-Pacific Islands.

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CHAPTER 6 RECONSTRUCTING THE LOCAL VEGETATION AND SEASONALITY OF THE LOWER EOCENE BLUE RIM SITE OF SOUTHWESTERN WYOMING USING FOSSIL WOOD

Fossils have been collected in the Eocene Bridger Formation of Wyoming for more than a century, but most attention has been devoted to the fauna (Murphey and Evanoff, 2011) and the plant remains are known only from a few scattered reports of individual taxa (Manchester and

Zavada, 1987; Manchester and Hermsen, 2000; Manchester et al., 2006; Allen, 2015a; Allen et al., 2015). The Blue Rim escarpment, exposing the lower Bridger Formation in southwestern,

Wyoming (Fig. 6-1) has yielded numerous well-preserved impressions of leaves and reproductive structures, dispersed pollen and spores, and silicified woods. The woods, preserved as stumps and logs, provide a focused view of the local diversity and environment of this area during the latest Early Eocene. A radiometric age of ~49.3 Ma has been estimated from just above the most productive fossil layer at Blue Rim (M.E. Smith, personal communication, 2016).

In this treatment, the anatomy of the Blue Rim woods is described and used to determine taxonomic affinities. In addition to the taxonomic treatment, wood characters are evaluated to interpret broad paleoclimate and paleoecological parameters. Specific gravity and vulnerability to freezing conditions are estimated from well-preserved woods, and specimens with complete diameters are used to estimate tree heights. Finally, the taxonomic affinities of the Blue Rim

(BR) wood assemblage are compared with other fossil wood assemblages from the Eocene of western North America.

Material and Methods

The Bridger Formation (upper Lower Eocene to lower Middle Eocene) is composed of mostly fluvial and reworked volcanic sediments (Murphey and Evanoff, 2011). This formation is well-known for its vertebrate fauna and is the stratotype for the Bridgerian North American Land

Mammal Age (Krishtalka et al., 1987; Murphey et al., 2001; Robinson et al., 2004). The local

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stratigraphy of Blue Rim was documented by Kistner (1973) who noted the occurrence of various fossils including permineralized wood.

Wood was subsequently collected at Blue Rim in the mid-1980s by Jane Landeen (who discovered one of the most productive quarry sites), S. R. Manchester, and others. A larger collection was made in 1995 by S.R. Manchester and S. Hack with additional specimens acquired in 2003, 2009, 2010, and 2014. These wood specimens come from eight different sites along the Blue Rim escarpment. Specimens (and slides) are housed in the paleobotanical collection of the Florida Museum of Natural History in Gainesville, FL (UF localities 00341S,

15761, 18289, 18591, 19031, 19225, 19338W, 19406). Other (non-wood) macrofossils have been collected from or very near to each of these sites with the exception of 18591 and 19406 which yielded only fossil wood. The BR wood specimens were mostly scattered, but occasional in situ stumps were encountered. Seven of the eight wood sites were within an ~2.6 km span of the Blue Rim escarpment, but locality UF 18591 was much further south and when included, the distance between the northernmost and southernmost wood sites expanded to ~4 km. The BR wood specimens were the subject of a preliminary study by S.R. Manchester and E.A. Wheeler presented at the 2006 Botanical Society of America annual meeting. They recognized four dicotyledonous diffuse-porous morphotypes, but did not provide specific taxonomic identifications.

Hand specimens were cut in transverse, radial, and tangential orientations with a Lortone slab saw with a 10 inch diamond blade. Resulting wafers were trimmed and mounted to glass slides with epoxy. Sections were ground to ~30 µm thick or less (if very dark) using a

“PetroThin” thin sectioning machine and coverslips were mounted with Canada balsam and

Citrisolv. Specimens were observed using a Nikon Eclipse E600 microscope and photographed

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with a Canon EOS Rebel Xsi camera. Photos received light balancing and saturation adjustments in Adobe Photoshop CS5. Descriptions follow the terminology and definitions outlined in the

IAWA List of microscopic features for softwood and hardwood identification (Wheeler et al.,

1989; Richter et al., 2004). When multiple specimens of a morphotype were included in a description, quantitative characters were reported as a range of the calculated lowest and highest mean and standard deviation of all the samples followed by the total range (of raw measurements) observed. Measurements of wood anatomical features were completed on photos using ImageJ (Rasband, 1997-onwards). Means, standard deviations, and other relevant calculations were completed using Microsoft Excel and rounded to the nearest whole number with the exception of tracheary and intervessel pits which were rounded to the tenths place. The presence or absence of wood characters were entered into the multiple entry key of the

InsideWood website (http://insidewood.lib.ncsu.edu) to obtain lists of taxa with the combinations of features observed in the fossil woods (InsideWood, 2004-onwards; Wheeler, 2011).

Angiosperm xylotypes were ordered using the list provided by the Linear Angiosperm

Phylogeny Group (Haston et al., 2009).

Two approaches were used to estimate the specific gravity of seven different well- preserved wood specimens. The first followed the methods of Wheeler et al. (2007a). Using

ImageJ (Rasband, 1997-onwards), 500 points (100 points, repeated 5 times) were randomly placed on an image of a transverse section taken at 40x total magnification. The number of times a point fell on lumen (vs. cell wall) was recorded. This allowed the percentage of wall material to be calculated, which was then multiplied by 1.05 (specific gravity estimate of swollen cell walls, thought to be similar in both dicotyledons and conifers) as indicated in Wheeler et al. (2007a).

The second approach used the work of Martínez-Cabrera et al. (2012) and required vessel

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diameter, fiber wall thickness, and fiber lumen diameter measurements, which were also completed in ImageJ (Rasband, 1997-onwards). Twenty five measurements of fiber wall thickness and corresponding fiber lumen diameter in the tangential direction were measured in addition to average vessel diameter (30 measurements, unless otherwise indicated). These were entered into the first equation in Table 1 of Martínez-Cabrera et al. (2012), SG = 0.802 + 1.346

(WLR) - 0.22 (LOGvdiam), where WLR is the average fiber wall thickness to lumen diameter ratio and LOGvdiam is the log of the average vessel diameter (Martínez-Cabrera et al., 2012). It is important to note the fibers and/or vessels were frequently compressed and distorted in the BR specimens during or prior to fossilization, reducing the chance that a point would fall in the lumen space and likely leading to inflated specific gravity estimates. Compression also affects the ability to obtain accurate measurements of the original vessel diameter and the fiber lumen diameter.

Vulnerability index (V) was also calculated for all Blue Rim woods (16 specimens, plus a few additional specimens in Appendix D) with both average vessel diameter and average vessel frequency. This index, which has been used to infer a plant’s ability to withstand water stress or freezing conditions, is calculated by simply dividing the mean tangential vessel diameter (µm) by the vessel frequency (Carlquist, 1975b, a, 1977; Wheeler, 1991). Finally, five methods

(McMahon, 1973; McMahon and Kronauer, 1976; Rich et al., 1986; Brown et al., 1989; Niklas,

1994; Feldpausch et al., 2011) were used to estimate tree height from complete stem diameters.

Systematics and Results

Gymnospermae

Division—Pinophyta Cronquist, Takht. & W. Zimm. ex Reveal

Family—Pinaceae Spreng. Ex Rudolphi

Genus—cf. Pinus L.

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Specimen—UF 19406-61964 (Figs. 6-2A-H).

Description—Growth rings intermediate between distinct and indistinct (but difficult to determine; variation may be due to preservational differences). Tracheids with large uniseriate pits (avg. = 18.7 µm in diameter, SD = 1.9 µm, Range: 16.2–20.9 µm, n = 5) on radial walls,

(Figs. 6-2C, 2D). The presence or absence of organic deposits in heartwood tracheids, average tracheid length, and tracheid size class not determined due to poor preservation. Some intercellular spaces present, but these areas distorted due to compression during fossilization.

Tracheids thin walled (Fig. 6-2B). Torus not well preserved, but appears regular and smooth in outline of torus and pit. Helical thickenings and callitroid thickenings not observed. Axial parenchyma not observed in either transverse or longitudinal sections. Ray tracheids present with small circular pits, but poorly preserved. Cross-field pitting not well enough preserved to determine. Rays average 198 µm long (SD = 91 µm, Range: 97–464 µm, n = 30). Rays of medium height (5 to 15 cells); mostly uniseriate, but occasionally 2-3 cells wide. Ray frequency averages to 10 per mm (Range: 6–16, n = 10). Normal axial resin canals present (Fig. 6-2A); scattered, distorted, averaging 105 µm in diameter (SD = 21 µm, Range: 82–148 µm, n = 9).

Radial canals present (diameter = ~30 µm, n = 1), but sparse and generally obscured in tangential section by the compressed nature of the specimen (Figs. 6-2G, 6-2H). No minerals or crystals observed.

Remarks—Wood poorly preserved, compressed, and distorted. Tracheary pits rarely visible. The absence of vessels and presence of large circular bordered pits on the tracheids indicates this wood is coniferous and thus the only non-angiosperm wood specimen from Blue Rim.

Discussion of Affinities—Among the conifers, only a few genera in Pinaceae (Cathaya,

Keteleeria, Larix, Picea, Pinus, and Pseudotsuga) have normal intercellular canals (Wu and Hu,

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1997; Richter et al., 2004). Traumatic canals, when they occur, are found throughout most of

Pinaceae (Richter et al., 2004). The axial canals in this specimen are diffuse and therefore not obviously traumatic; however that cannot be said with certainty for the radial canals. Keteleeria has only axial canals, but Cathaya, Pseudotsuga, Pinus, Picea, and Larix have both normal radial and axial canals as was observed in this specimen (Hu and Wang, 1984; Richter et al.,

2004). This specimen has some axial canals in pairs, which is common in Pseudotsuga and

Larix. Axial canals in Pinus can generally be distinguished from those of other genera because of their thin-walled epithelial cells and larger diameters (Wu and Hu, 1997; Richter et al., 2004).

However, Hilton et al. (2016) note that thin-walled epithelial cells occur occasionally in Larix,

Picea, and Pseudotsuga. It is difficult to distinguish epithelial cells from the surrounding tracheids in the BR specimen; however, their absence may be a consequence of being originally thin-walled making them less likely to preserve. The diameter of axial resin canals in extant species of Larix, Pseudotsuga, and Picea is small (~40–100 µm), whereas species of Pinus often have medium sized canals (~100–170 µm, Richter et al., 2004). The axial resin canals in the BR specimen range from 82 µm to 148 µm in diameter with an average of 105 µm. These measurements may slightly underestimate the diameter of the canals in life because of distortion in the fossil. In addition, Larix often has biseriate (rather than uniseriate) tracheid pitting in its radial walls (Jagels et al., 2001; Richter et al., 2004) and Cathaya has prominent growth rings and a lower ray frequency (4-8 per mm, Hu and Wang, 1984) compared to the BR specimen (6-

16 per mm, avg. 10).

The oldest fossils assigned to Pinaceae are Jurassic (Smith et al., 2016). Pinus, Picea, and

Cathaya have been recovered from Cretaceous sediments (Liu and Basinger, 2000; Wang et al.,

2000; Ryberg et al., 2012), while the earliest known fossil of Larix is middle Eocene (~45 Ma,

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LePage and Basinger, 1991; Jagels et al., 2001; Labandeira et al., 2001) and Pseudotsuga fossils have been recovered from the early Oligocene (Hermann, 1985; Wang et al., 2000; Yabe, 2011).

Given the uniseriate tracheary pitting, size of the resin canals, and probable thin-walled epithelial cells, this specimen is most likely a representative of Pinus. Wood of Pinaceae cf. Pinus is present in the Eocene Clarno Formation of Oregon, but this taxon has well-defined distinct growth rings and larger axial canals than the BR specimen (Wheeler and Manchester, 2002).

Wood assignable to Pinus has also been recovered from the Eocene Lamar River Formation in

Yellowstone National Park, but those specimens also have well-defined growth rings, unlike the

Blue Rim specimen (Knowlton, 1899; Fritz and Fisk, 1978).

Angiospermae

Division—Magnoliophyta Cronquist, Takht. & W. Zimm. ex Reveal

Family—Canellaceae Mart.

Taxon—Canellaceae Xylotype 1

Specimen—UF 18591-33036 (Figs. 6-3A-I).

Description—Growth boundaries indistinct with occasional tangential lines where cells are more crushed (possible latewood). Wood diffuse-porous with a high proportion of widely spaced, solitary vessels and occasional multiples of two (Figs. 6-3A, 3B). Perforation plates scalariform with 10 to 20 bars (counted 13–20 bars on 7 different plates, Figs. 6-3C, 6-3E, 6-3H, 6-3I).

Intervessel pits not observed (likely due to the high proportion of solitary vessels). Mean tangential diameter of vessel lumina 57 µm (SD = 14 µm, Range: 28–87 µm, n = 30). Mean vessel frequency 12 mm2 (Range: 4–18, n = 6). Some vasicentric tracheids present. Fiber pits visible in radial section (possibly in tangential section too, but preservation is not as good).

Fibers thin to thick walled. Axial parenchyma likely rare to absent as it was not observed in any section. Rays exclusively uniseriate (tangential section poorly preserved). Aggregate rays absent. 411

Ray height averages to 200 µm (SD = 85 µm, Range: 91–388 µm, n = 23). Ray cellular composition poorly preserved; appears to have procumbent body cells and 1-2 rows of upright and/or square marginal cells. Ray frequency ranges from 5 to 20 per mm (avg. = 10, n = 10). No storied structure, intercellular canals, or crystals observed.

Vulnerability Index—Specimen UF 18591-33036 has an estimated V of 4.8.

Discussion of Affinities—This specimen appears to be the lone representative identified as

“Type III” from Manchester and Wheeler (2006). They noted the combination of characters suggested affinities to Ericaceae or Myrtaceae. Leaves of Syzygioides americana (an extinct genus in the Myrtaceae, Manchester et al., 1998) occur at Blue Rim, so affinities with Myrtaceae might be a reasonable hypothesis. However, further investigation of the anatomy of this wood suggested Canellaceae based on a few distinct characters including: scalariform perforation plates, mostly solitary vessels, vasicentric tracheids, and uniseriate rays.

With this in mind, the diagnostic characters (2p, 5p, 9p, 14p, 16p, 30p, 96p; Wheeler et al., 1989) were entered into InsideWood in an attempt to identify this morphotype. This search yielded six matches: Balanops australiana (Balanopaceae), Canella winterana, Cinnamosma sp.,

Pleodendron sp. (Canellaceae), Columellia sp. (Columelliaceae), and Tepuia venusta (Ericaceae,

InsideWood, 2004-onwards). With the addition of three characters (41p, 46p, and 47p) with one mismatch allowed, the results were narrowed to Canella winterana and Cinnamosma sp.

(InsideWood, 2004-onwards). The character that did not match either of these results was 46 (≤ 5 vessels per square mm). Based on this result, a detailed comparison to both the modern genera in

Canellaceae and the fossil species Wilsonoxylon edenense N. Boonchai et Manchester was undertaken.

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Wilson (1960) examined the wood anatomy of Canellaceae. Comparing his descriptions to the BR Canellaceae Xylotype 1 specimen, two of the five currently accepted extant genera can be eliminated from consideration. All extant genera have scalariform perforation plates, but

Cinnamodendron has significantly more bars (50–100) than the BR specimen (13–20). In addition, the BR specimen has uniseriate rays, yet Wilson (1960) noted Warburgia has rays ranging from 1-4, typically 2-3, cells wide. Vessel diameter and frequency is similar between the remaining three genera, Canella, Cinnamosma, Pleodendron, and the BR specimen (Wilson,

1960; InsideWood, 2004-onwards). Vessels in Pleodendron are usually solitary with a few pairs

(similar to Canellaceae Xylotype 1), whereas they are usually solitary or occasionally in small clusters in Canella and Cinnamosma (Wilson, 1960). However, vessels in Pleodendron tend to be arranged in a diagonal, radial, or dendritic pattern (InsideWood, 2004-onwards), which was not observed in the fossil specimen. Canella (5–28), Cinnamosma (11–49), and Pleodendron

(15–40) have a larger range of bars in their scalariform perforation plates (which can vary to reticulate) than the BR specimen (13–20), but bars in the fossil material may be undercounted due to preservational bias (Wilson, 1960). Canellaceae Xylotype 1 has exclusively uniseriate rays, similar to the predominately uniseriate rays found in Canella, Cinnamosma, and

Pleodendron (Wilson, 1960). A few other differences include that Canellaceae Xylotype 1 has thin to thick walled fibers, but they are thick to very thick in Canella, Cinnamosma, and

Pleodendron. Paratracheal axial parenchyma is present in the extant genera and Cinnamosma can have oil cells, but these features were not observed in the fossil. Finally, rhombohedral crystals are present in Canella and Cinnamosma, but not Pleodendron or the BR fossil specimen

(Wilson, 1960). Based on these comparisons, it is not possible to determine which modern genus

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of Canellaceae might be the closest to the BR specimen, but it is probably not Cinnamodendron or Warburgia.

Wilsonoxylon edenense (Canellaceae), from the nearby Eocene Big Sandy Reservoir fossil flora (Boonchai and Manchester, 2012), shares the character of scalariform perforation plates with 10-20 bars with the BR specimen and was compared in more detail. Both W. edenense and Canellaceae Xylotype 1 have indistinct growth ring boundaries with narrower (W. edenense) or crushed (UF 18591-33036) fibers in the radial direction. Canellaceae Xylotype 1 is diffuse-porous and the Big Sandy Reservoir taxon ranges from semi-ring to diffuse-porous. The

BR specimen and W. edenense have mostly solitary vessels with occasional pairs. These may represent where the section crossed overlapping end walls of two vessel elements. However, vessel density is significantly different between W. edenense (40-60 mm2; lowest was 22 mm2 in latewood) and the BR specimen (avg. 12 mm2). The mean tangential diameter of vessels in

Canellaceae Xylotype 1 is ~57 µm, whereas vessel diameters average to 35 and 40 µm in the Big

Sandy Reservoir specimens (Boonchai and Manchester, 2012). It is possible these variations in vessel diameter and density are due to sampling different parts of the plant (e.g., trunk vs. branch) or varying wood maturities. Ray cellular composition is similar between the Blue Rim and Big Sandy Reservoir material. However, W. edenense is clearly distinguished from the BR specimen because it has two- to three-seriate rays, rather than uniseriate. This character, ray width, also precludes the BR specimen from conforming to the generic diagnosis of

Wilsonoxylon. It does not seem advisable to emend the diagnosis of Wilsonoxylon to include this specimen because many of the other diagnostic characters including the presence of diffuse axial parenchyma, vessel-ray pits, and obvious idioblasts in the axial and ray parenchyma are not preserved. Furthermore, Canellaceae Xylotype 1 is only represented by a single specimen. Mean

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ray height is also shorter in the BR specimen (200 µm) than in the Big Sandy Reservoir specimens (>300 µm, Boonchai and Manchester, 2012).

This Blue Rim wood specimen is not well enough preserved to identify to the generic level, but it does fit the broad characters of the family Canellaceae. Extant Canellaceae are generally small to medium-sized evergreen trees. The five genera are disjunct and found in tropical and subtropical East Africa (Warburgia), Madagascar (Cinnamosma), and the Americas

(Canella, Cinnamodendron, and Pleodendron) including South America, the Caribbean, and south Florida (Salazar, 2006; Mabberley, 2008; Salazar and Nixon, 2008; Müller et al., 2015).

However, the range of Canellaceae extended to at least southwestern Wyoming in the Eocene based on the presence of Wilsonoxylon edenense and this specimen from Blue Rim.

Family—Fabaceae Lindl.

Subfamily—Caesalpinioideae DC. (traditional/s.l.)

Genus—Peltophoroxylon Müller-Stoll et Mädel

Species—Peltophoroxylon diversiradii S.E. Allen, sp. nov.

Diagnosis—Diffuse-porous. Vessels predominantly grouped in radial multiples of 2 or 3 or solitary; perforation plates simple. Intervessel pits generally alternate, small to medium in size.

Prominent paratracheal axial parenchyma: vasicentric, aliform, occasional lozenge-aliform and confluent. Occasional marginal parenchyma bands present or bands >3 cells wide. Rays mostly biseriate, occasionally uniseriate, rarely wider. Ray cellular composition variable from homocellular procumbent to heterocellular with procumbent body cells and one to three rows of upright/square marginal cells. No storied structure.

Holotype, hic designates—UF 19338W- 61966 (Figs. 6-4B, 6-4D, 6-4E, 6-4H, 6-4I).

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Repository—Florida Museum of Natural History (FLMNH), Gainesville, Florida.

Type locality—Blue Rim, Sweetwater County, Wyoming.

Stratigraphic position and age—Lower Bridger Formation, latest Early Eocene.

Paratypes—UF 15761-56323; UF 18591-33042; UF 19338W-61965 (Figs. 6-4A, 6-4C, 6-4F, 6-

4G; 6-5A-E).

Etymology—The specific epithet is Latin for “diverse rays.” Extant species of Peltophorum and many fossil species of Peltophoroxylon have homocellular rays, with all cells procumbent.

However, this taxon has predominately biseriate rays that are both homocellular (all cells procumbent) and heterocellular (procumbent body cells and 1-3 rows of upright/square marginal cells).

Description—Growth ring boundaries variable from weakly defined by irregular and inconsistent bands of marginal parenchyma to indistinct; wood diffuse-porous. Vessel arrangement scattered with a weak radial pattern. Vessels grouped in occasional clusters or radial multiples of 4 or more, but more commonly radial multiples of 2 or 3 or solitary vessels.

Infrequent, short tangential bands of vessels present. Solitary vessel outline not angular; perforation plates simple. Intervessel pits rarely opposite, usually alternate with a mean diameter across the samples of 5.3 µm (SD = 0.3 µm, n = 10, UF 19338W-61965) to 7.1 µm (SD = 0.8

µm, n = 10, UF 19338W-61966) with a total range of 4.8–8.8 µm. Vestured pits not observed.

Vessel-ray pits are small, inconspicuous, and similar to intervessel pits (Fig. 6-5D). Helical thickenings not observed. Mean tangential diameter of vessel lumina 45 µm (SD = 17 µm, n =

30, UF 19338W-61966) to 74 µm (SD = 20 µm, n = 30, UF 18591-33042) with a total range of

13–108 µm. Vessel frequency variable (Range: 0 to 46 mm2, n = 3). Mean vessel element length

173 µm (SD = 40 µm, n = 11, UF 15761-56323) to 213 µm (SD = 88 µm, n = 30, UF 19338W-

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61966) with a total range across all specimens of 79–517 µm. Tyloses absent. Ground tissue pits not observed. Non-septate fibers present, no septate fibers observed. Fibers vary from thin to very thick walled. Paratracheal axial parenchyma present with patterns including vasicentric, aliform, occasional lozenge-aliform, and confluent (Figs.6-4A-C, 6-5A). Occasional banded parenchyma >3 cells wide and marginal parenchyma bands present. Axial parenchyma strand length varies from 3 to >8 cells. Rays generally 1–2 cells wide, very rarely wider, with two- seriate the most common condition (Figs. 6-4F-G, 6-5B). Rays average 189 µm (SD = 77 µm, n

= 30, UF 19338W-61966) to 263 µm long (SD = 93 µm, n = 30, UF 15761-56323) with a total range of 64–522 µm. Ray cellular composition variable. Rays homocellular procumbent or heterocellular with procumbent body cells and one, two, or three rows of upright and/or square marginal cells. Ray frequency ranges from 2 to 12 per mm (n = 3). No storied structure or intercellular canals observed. Rare prismatic crystals in chambered axial parenchyma cells.

Small irregular to rounded deposits also present in ray cells.

Vulnerability Index—Vulnerability index averages 5.2 (SD = 4.4, n = 3); however, the range

(1.9–10.3) is large due to variations in vessel frequency among specimens.

Remarks—The prominent aliform to confluent axial parenchyma differentiates this wood morphotype from others at Blue Rim. The absence of tyloses and radial canals readily distinguishes this from the co-occurring and most common BR wood species, Edenoxylon parviareolatum Kruse. Peltophoroxylon diversiradii corresponds to wood “Type IV” identified by Manchester and Wheeler (2006) who noted these characters are found in Fabaceae,

Sapindaceae, and Oleaceae. Further investigations (discussed below) indicate these wood specimens correspond to Fabaceae.

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Discussion of Affinities—Although the differences in wood anatomy between the traditional subfamilies of Fabaceae are subtle, they can be helpful (Baretta-Kuipers, 1981; Wheeler and

Baas, 1992; Ogata et al., 2008). Members of Mimosoideae have exclusively homocellular rays, whereas ~30% of Caesalpinioid genera and ~20% of genera in Papilionoideae have heterocellular rays (Baretta-Kuipers, 1981; Wheeler and Baas, 1992; Ogata et al., 2008). Small, low rays with exclusively procumbent cells are rare in Caesalpinioideae and Papilionoideae, but when present in either of these subfamilies, the rays are storied (Baretta-Kuipers, 1981).

Approximately 75% of Papilionoid genera have all elements storied, whereas this is absent in

Mimosoideae and found in less than 25% of Caesalpinioid genera (Baretta-Kuipers, 1981;

Wheeler and Baas, 1992; Ogata et al., 2008). In addition, members of Caesalpinioideae and

Mimosoideae rarely have helical thickenings or ring porosity, but both of these characters are common in Papilionoideae (Wheeler and Baas, 1992). Furthermore, Caesalpinioid genera are the least likely of the three subfamilies to have 1 to 2 celled parenchyma strands; ~35% of taxa have strands with >4 cells, similar to Peltophoroxylon diversiradii (Baretta-Kuipers, 1981; Wheeler and Baas, 1992). As neither storied structure nor small, low, homocellular rays are present in P. diversiradii, both Papilionoideae and Mimosoideae are less likely to accommodate this fossil.

This process of elimination suggests the fossil specimens represent Caesalpinioideae.

The Caesalpinioideae subfamily has approximately 2250 species in over 170 genera and

4 tribes (Lewis et al., 2005-onwards; LPWG, 2013a, b). Recent phylogenetic work on Fabaceae has found Caesalpinioideae to be paraphyletic; Papilionoideae and Mimosoideae are clades that arose from within Caesalpinioideae (LPWG, 2013a, b). The Legume Phylogeny Working Group recently released a new subfamily level classification for Fabaceae (LPWG, 2017). In this, the legumes are now composed of six subfamilies; the former Mimosoideae is now a clade in a

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recircumscribed Caesalpinioideae, Papilionoideae is still a subfamily, and Cercidoideae,

Detarioideae, Dialioideae, and Duparquetioideae are newly recognized at the rank of subfamily

(LPWG, 2017). Here, the use of Caesalpinioideae is in the broader, traditional circumscription

(one of three subfamilies within Fabaceae). A brief commentary about the new classification and its potential effect on the placement of Peltophoroxylon diversiradii is provided at the end of this discussion.

Taxonomic affinities within extant Caesalpinioideae. When the most conspicuous and well-preserved characters of this morphotype were entered into InsideWood, the results also focused on the Caesalpinioideae including the genera of Baikiaea, Berlinia, Burkea, Caesalpinia,

Julbernardia, and Oxystigma (InsideWood, 2004-onwards; Wheeler, 2011). However, none of these genera are a close match to the BR specimens based on the presence of one or more of the following characters: polygonally shaped and/or larger intervessel pits (Baikiaea, Burkea,

Julbernardia, and Oxystigma), very well-defined, thick parenchyma bands (Baikiaea,

Oxystigma), much wider vessels (>200 µm in diameter, Berlinia), and axial canals (Oxystigma,

InsideWood, 2004-onwards). Whereas none of these genera match the Blue Rim species, further comparison with the Caesalpinioideae is warranted. Two of the fossil specimens have prismatic crystals in chambered axial parenchyma cells; a common feature in Caesalpinioideae (Melandri and Espinoza de Pernía, 2009).

Baretta-Kuipers (1981) divided the Caesalpinioideae into two groups based on wood anatomy. The first group, composed of the tribes Caesalpineae, Cassieae, and Cercideae, is characterized by homocellular rays averaging 450 µm in height. The wood anatomy of eight genera within Caesalpinieae has been explored further and of these, Dimorphandra shares the most characters with the BR specimens (Espinoza de Pernía and Melandri, 2006). Mora is also

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similar, but generally has homocellular rays, whereas the fossils have both homocellular and heterocellular rays. Characters that exclude the other genera studied in Caesalpinieae include: regular very large parenchyma bands, intervessel pits that are too large, mostly or exclusively uniseriate rays, or having storied structure (Espinoza de Pernía and Melandri, 2006). The second group within Caesalpinioideae includes the tribes Detarieae and Amherstieae (Amherstieae is not currently recognized as a tribe, Lewis et al., 2005-onwards; LPWG, 2013b) and has mostly heterocellular rays with an average height of 650 µm (Baretta-Kuipers, 1981). The wood anatomy of ten genera in the tribe Detarieae has been explored in detail and four (Copaifera,

Elizabetha, Eperua, and Heterostemon) can be eliminated from consideration due to either the presence of axial intercellular canals or mostly/exclusively uniseriate rays as neither of these characters are present in Peltophoroxylon diversiradii (Melandri and Espinoza de Pernía, 2009).

Many of the genera in both Caesalpinieae and Detarieae have large intervessel pits, but Brownea,

Cynometra, Dimorphandra, and Mora tend to have smaller pits that are more consistent with P. diversiradii (Melandri and Espinoza de Pernía, 2009). However, these genera have other characters that do not align with the fossil material (InsideWood, 2004-onwards). The numerous genera and similarity of wood characters across the Caesalpinioideae, in conjunction with a few important, but indeterminable characters in the fossil specimens, precludes a taxonomic assignment to an extant genus in Caesalpinioideae. Therefore, fossil wood assigned to Fabaceae from the Western Interior of North America and extinct genera of Caesalpinioideae were examined.

Comparison to other fossil wood of Fabaceae. Three fossil legume woods from the middle Eocene Clarno Formation in Oregon were also compared with Peltophoroxylon diversiradii (Table 6-1, Wheeler and Manchester, 2002). All three Clarno taxa,

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Dichrostachyoxylon herendeenii, cf. Euacacioxylon, and cf. Mimosoxylon, have a larger average tangential diameter of vessels and differing ray width and axial parenchyma patterns as compared to P. diversiradii (Table 6-1, Wheeler and Manchester, 2002). Intervessel pits are larger in two of the Clarno taxa and average ray height in D. herendeenii is similar to the BR specimens, but it is greater in both cf. Euacacioxylon and cf. Mimosoxylon (Table 6-1, Wheeler and Manchester, 2002). Although there is some overlap in characters between each of the Clarno legumes and Peltophoroxylon diversiradii, there are enough differences to conclude they are distinct.

Fritz and Fisk (1978) noted a possible fabaceous wood from Yellowstone National Park.

Recent examination of “Laurinoxylon pulchrum" Knowlton indicates it is a legume, rather than

Lauraceae (Elisabeth Wheeler, personal communication, 2016; InsideWood, 2004-onwards).

However, “Laurinoxylon pulchrum" differs from the Blue Rim specimens in having locally storied parenchyma and semi-ring porosity (Wheeler and Baas, 1992; InsideWood, 2004- onwards). Legume wood has also been documented from Eocene strata in the Willwood

Formation in Park County, Wyoming. Whereas the Willwood material has similar features to

Peltophoroxylon diversiradii in transverse section, it differs in having well-defined storied structure in longitudinal section (Wheeler and Baas, 1992).

Assignment to Peltophoroxylon. Other fossil genera of Caesalpinioideae were investigated because the Blue Rim specimens are not well aligned with a fossil taxon from nearby floras. Müller-Stoll and Mädel (1967) established multiple genera for fossil legume wood. Peltophoroxylon was the best match to the Blue Rim specimens, in part, because the rays range to having one row of upright marginal cells rather than being exclusively homocellular procumbent. Peltophoroxylon includes fossil woods with features similar to extant Cassia,

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Peltophorum, and Xylia (Müller-Stoll and Mädel, 1967; Bande and Prakash, 1980; Awasthi,

1992). Prakash (1975) later excluded fossil woods from Peltophoroxylon with similarities to extant Cassia and created a new fossil genus Cassinium. However, the broader diagnosis of

Peltophoroxylon is retained here as these two genera are very similar and minor differences are challenging to recognize in fossils.

Multiple species of Peltophoroxylon have been documented, primarily from the Miocene of southern Asia (Bande and Prakash, 1980; Awasthi, 1992; InsideWood, 2004-onwards). Most of these species have significantly larger vessel diameters than the Blue Rim taxon and many have exclusively homocellular (all cells procumbent), wider, or storied rays (Awasthi, 1992;

InsideWood, 2004-onwards). In the Western Hemisphere, Peltophoroxylon uruguayensis, was recently documented from the late Pleistocene of eastern Argentina (Ramos et al., 2014).

Peltophoroxylon uruguayensis shares the feature of predominately biseriate rays with P. diversiradii, but among other characters, it differs in that the rays are exclusively homocellular procumbent (Ramos et al., 2014). The most similar taxon to the Blue Rim specimens is

Peltophoroxylon sp. from the late Eocene marine sands in Helmstedt, Lower Saxony, Germany

(Gottwald, 1992). This species has many features in common with Peltophoroxylon diversiradii including: a lack of clear growth rings, small diameter vessels, similar sized intervessel pits, and the presence of crystals (Gottwald, 1992). Peltophoroxylon diversiradii differs from the

Helmstedt taxon in having predominately biseriate rather than uniseriate rays and heterocellular rays that can have one or more rows of square or upright marginal cells, rather than only weakly heterocellular rays with an extended marginal cell.

Extant Peltophorum remains within Caesalpinioideae even with the new subfamily classification of legumes (LPWG, 2017). However, based on what is visible, the fossil material

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does not appear to have vestured pits—a feature common in Fabaceae including extant

Peltophorum. However, vestured pits are absent in the newly recognized subfamilies of

Duparquetioideae, Cercidoideae, and most genera of Dialioideae (Quirk and Miller, 1985;

Herendeen, 2000; Gasson et al., 2003; Herendeen et al., 2003; Bruneau et al., 2008; LPWG,

2017). Storied rays are common in Dialioideae (LPWG, 2017), but they were not observed in the fossil material. Further investigation may reveal that Peltophoroxylon diversiradii is more closely affiliated with one of the other (e.g., Cercidoideae) newly recognized subfamilies of

Fabaceae.

Family—Anacardiaceae R. Br.

Genus—Edenoxylon Kruse

Species—Edenoxylon parviareolatum Kruse emend. N. Boonchai et Manchester

Specimens—UF 00341S-61961; UF 15761-56320; UF 18289-56305, 56306, 56308; UF 18591-

33008, 33021, 33023, 33030, 33034, 33041 (Figs. 6-6A-H, 6-7A-H, 6-8A-J).

Description—Growth ring boundaries indistinct (occasional changes in fiber preservation, but not consistent or continuous) to absent. Wood diffuse-porous with vessels in a radial pattern.

Occasional radial multiples of 5 to 6 or rare clusters, but more commonly radial multiples of 2 to

4 or solitary vessels. Solitary vessel outline not angular. Perforation plates simple. Minute to small intervessel pits alternate to rarely opposite with an average across specimens of 3.8 µm

(SD = 0.4 µm, n = 10, UF 00341S-61961) to 4.8 µm (SD = 0.7 µm, n = 10, UF 18591-33030) with a total range of 3.2–6.6 µm. Vessel-ray pitting not preserved on many specimens, but pits oblong rounded or horizontal with much reduced borders to apparently simple when present (Fig.

6-7G). Vestured pits and helical thickenings not observed. Mean tangential diameter of vessel

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lumina across all specimens 47 µm (SD = 15 µm, n = 30, UF 18591-33030) to 78 µm (SD = 17

µm, n = 30, UF 18289-56306) with a total range of 14–113 µm. Vessels per square mm ranges from 8 to 54. Vessel element length could only be measured for two specimens and averages 80

µm (SD = 31 µm, n = 30, UF 18591-33034) to 108 µm (SD = 46 µm, n = 19, UF 18289-56306) with a total range of 30–195 µm. Tyloses present (occasionally appearing sclerotic), often extensive and obscuring vessel element end walls. Fibers with simple to minutely bordered pits.

Helical thickenings in ground tissue fibers not observed. Both septate and non-septate fibers present (Fig. 6-7H). Fibers occasionally very thin or very thick walled, more frequently thin to thick walled. Axial parenchyma present, but uncommon; diffuse apotracheal, scanty paratracheal, and in weak ~marginal bands. Axial parenchyma with approximately 3 to greater than 8 cells per strand. Rays mostly 1-2 cells wide; occasionally 3 (wider in rays with radial canals). When single cells present in center of multiseriate ray, width of uniseriate portion equals width of neighboring multiseriate portion. Aggregate rays absent. Ray height averages 167 µm

(SD = 48 µm, n = 30, UF 18289-56308) to 253 µm (SD = 98 µm, n = 30, UF 18591-33008) with a total range of 94–487 µm. Ray cellular composition variable ranging from body cells procumbent with 1 to >4 rows of upright/square cells to procumbent, square, upright mixed throughout ray. Rays per mm ranges from 6 to 30. No storied structure; radial canals present, but variable in frequency among specimens. Average length of rays with single canals across specimens 345 µm (SD = 129 µm, n = 6, UF 18289-56308) to 509 µm (SD = 288 µm, n = 2, UF

18289-56305) with a total range of 194–712 µm. Average width of rays with single canals among specimens 60 µm (SD = 6 µm, n = 3, UF 18591-33030) to 98 µm (SD = 18 µm, n = 14,

18591-33023) with a total range of 47–136 µm. Average length of the canal opening across specimens with one canal in a ray 50 µm (SD = 16 µm, n = 6, UF 18289-56308) to 92 µm (SD =

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42 µm, n = 2, UF 18289-56305) with a total range of 26–121 µm. Average width of the canal opening among specimens with one canal in a ray 28 µm (SD = 4 µm, n = 3, UF 18591-33030) to 61 µm (SD = 17 µm, n = 14, UF 18591-33023) with a total range of 21–97 µm. Rays with two radial canals (three examples measured from all specimens) range from 437 to 499 µm long by

71 to 123 µm wide. Within these rays, canal size ranges from 35 to 81 µm long by 21 to 70 µm wide. Radial canals generally oblong in shape, but occasionally more rounded. Well-preserved canals with a ring of well-defined (epithelial) cells around the inside of the canal opening.

Prismatic crystals present; common in upright/square and procumbent ray cells, occasionally in non-ray cells (axial parenchyma and/or fibers). Rarely more than one crystal of the same size per cell. Crystals in the ray cells average 16 µm (SD = 2 µm, n = 5, UF 18591-33030) to 20 µm (SD

= 3 µm, n = 13, UF 18591-33021) in the longest dimension with a total range of 12–29 µm.

Specific Gravity—Two approaches were used to estimate the specific gravity of six specimens of this wood morphotype. Specific gravity averages to 0.75 (SD = 0.10, Range: 0.58–0.87) using the methods of Wheeler et al. (2007a), whereas using equation 1 of Martínez-Cabrera et al.

(2012) the average specific gravity is 1.05 (SD = 0.20, Range: 0.82–1.35).

Vulnerability Index—Vulnerability indices were calculated for 10 of the 11 Edenoxylon parviareolatum specimens (all except UF 18591-33041) for an average of 3.0 (SD = 1.9, Range:

1.4–5.7). When one of the cf. Edenoxylon parviareolatum specimens (UF 18591-33020, see

Appendix D) was included the average rose to 3.1 (SD = 1.8). The range did not change.

Remarks—This is the most common wood type at Blue Rim and is represented by stems of varying diameters from different sites across the escarpment. Most samples are just small fragments of larger logs or branches (e.g., UF 18591-33008 is ~3.5 cm in diameter), but they are occasionally much larger (e.g., UF 18591-33023 is ~30.5 cm in diameter). Although all BR

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specimens with numerous tyloses, radial canals, and prismatic crystals are considered to be a single morphotype, there are minor differences. A few specimens (e.g., UF 18289-56306, UF

18591-33021 and UF 18591-33023) have significantly lower vessel frequency (~8-20 mm2) as compared to the other specimens (~24-44 mm2). This variation might be due to differences in wood maturity or origin in the plant (e.g., trunk vs. branch wood). Fichtler and Worbes (2012) found large differences in vessel frequency within a species and between sites. The frequency of radial canals is also variable among specimens. A few specimens (e.g., UF 18289-56308 and UF

18591-33023) have numerous radial canals, but they are rare in other specimens (e.g., UF

00341S-61961 and UF 18591-33021). The frequency of radial canals has been shown to vary greatly between individuals, the location in the stem (e.g., close to the pith), or the maturity of the wood (Chattaway, 1951; Terrazas and Wendt, 1995).

Discussion of Affinities—The most distinguishing feature of this morphotype, radial intercellular canals, is found in several families of the Sapindales including Anacardiaceae and

Burseraceae, in addition to some species of Fabaceae, Apiaceae, Araliaceae, Moraceae,

Clusiaceae, Dipterocarpaceae, and Euphorbiaceae (InsideWood, 2004-onwards; Carlquist, 2012).

The rhomboidal prismatic calcium oxalate crystals found in many of the rays of these specimens can also be of systematic value (Carlquist, 2012).

When the characters 2p, 5p, 13p, 22p, 24p, 25p, 56p, 97p, 130p, and 136p were entered into InsideWood with 0 mismatches allowed, there was one result, Myracrodruon urundeuva

(Anacardiaceae, Wheeler et al., 1989; InsideWood, 2004-onwards; Wheeler, 2011). However, all intervessel pit size categories were scored as unknown for this taxon on InsideWood. Further investigation revealed the intervessel pits of Myracrodruon were documented as ≥10 µm in the work by Terrazas Salgado (1994), which is significantly larger than any of the BR specimens.

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With the same character list as above and one mismatch allowed (ignoring all with the mismatch of radial canals) the results included Pistacia terebinthus and Trichoscyphya arborea in the

Anacardiaceae, Canarium indicum (Burseraceae), Mammea africana (Calophyllaceae), and

Baloghia sp. (Euphorbiaceae, InsideWood, 2004-onwards). Overall, Anacardiaceae was the best fit, which matches the findings of Manchester and Wheeler’s (2006) wood “Type I”, which they also identified as Anacardiaceae.

Taxonomic affinities within extant Anacardiaceae. The minute to small (<7 µm) intervessel pits in the Blue Rim specimens were used to determine which extant genera of

Anacardiaceae to compare with the fossils. This character is usually consistent even if the wood is of variable maturity or from a different part of the plant. Faguetia, Haplorhus, Lithraea,

Loxostylis, Micronychia, Rhus, and Trichoscyphya have intervessel pits under 7 µm (Terrazas

Salgado, 1994). However, Faguetia, Lithraea, and Micronychia do not have radial canals, which is a significant contrast with the BR specimens, so they were not considered further.

The remaining genera, Haplorhus, Loxostylis, Rhus, and Trichoscypha, are all members of the tribe Rhoeae (Pell, 2004). Haplorhus, an evergreen shrub or small tree found in Peru and

Chile, has small intervessel pits (Terrazas Salgado, 1994), but none of the other quantitative characters examined are in the same range as the BR specimens. In addition, Haplorhus has homocellular procumbent rays with very few prismatic crystals (Terrazas Salgado, 1994), which is not in agreement with the Blue Rim material. Loxostylis, a small evergreen tree or shrub found in South Africa, is one of a few genera in Anacardiaceae with toothed leaf margins (Terrazas

Salgado, 1994). Vessel frequency and diameter in Loxostylis matches the ranges observed on the

BR specimens. Furthermore, ray height in Loxostylis is on the shorter side for Anacardiaceae with an average of 318 µm (Terrazas Salgado, 1994). Rhus can be evergreen or deciduous and is

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found in temperate to tropical regions of Asia and North America (Terrazas Salgado, 1994).

Some species of Rhus have rays <300 µm long and vessel frequency and diameter are also similar to the BR specimens. Trichoscypha, an evergreen tree from tropical West Africa, has silica bodies and significantly longer rays (Terrazas Salgado, 1994) than the BR Edenoxylon specimens.

Additional characters that are well-preserved in the Blue Rim Edenoxylon (tyloses, fibers, axial parenchyma, ray cellular composition, and crystals) were compared to the three remaining genera (Loxostylis, Rhus, and Trichoscypha). Although none of these have characters that specifically exclude them, Rhus is the best match with the fossil specimens because it has frequent prismatic crystals in both marginal and procumbent ray cells and similar vessel-ray pits

(characters 31 and/or 32, InsideWood, 2004-onwards). Furthermore, Rhus is the most geographically widespread taxon today and both Loxostylis and Trichoscypha are confined to

Africa (Terrazas Salgado, 1994). Although the wood of Rhus is often ring-porous (Boonchai and

Manchester, 2012), a few species, including Rhus laurina, are diffuse-porous (InsideWood,

2004-onwards). Most of the diffuse-porous species have wider vessels and much larger intervessel pits than observed on the BR specimens (Boonchai and Manchester, 2012). Leaves assigned to Rhus nigricans (Lesquereux) Knowlton in the Green River flora have also been found at Blue Rim (MacGinitie, 1969). However, this wood morphotype might not represent a living genus. At least one extinct anacardiaceous genus, Pentoperculum, is known from fruits of tribe Spondioideae (Manchester, 1994; Collinson et al., 2012) also found at Blue Rim.

Accordingly, it is necessary to compare these specimens to the fossil wood genus, Edenoxylon

(Anacardiaceae).

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Comparison to Edenoxylon parviareolatum. Edenoxylon parviareolatum, established by Kruse in 1954, is an anacardiaceous fossil wood that was first described from the Green River

Formation Hays’ Ranch site (~16 miles to the east of Farson) in southwestern Wyoming and later was found to be represented by numerous specimens from the Big Sandy Reservoir (BSR) flora, also from southwestern Wyoming (Kruse, 1954; Boonchai and Manchester, 2012). This species is thought to be subtropical, in part, because of the taxonomic affinities of the other woods recovered at BSR including Palmoxylon macginitiei Tidwell, a species of palm (Boonchai and Manchester, 2012).

Edenoxylon parviareolatum from BSR has growth ring boundaries weakly defined by a change in fiber radial diameter and marginal parenchyma. The BR specimens have absent to indistinct growth rings, although specimen UF 18591-33034 did have variations in fiber preservation across the transverse section. The distinctness of growth rings can vary within an individual tree as rings tend to be more obvious in trunks than in branches (Tarelkin et al., 2016).

Furthermore, coding of growth ring distinctness can vary between researchers and some of the features that define growth rings such as changes in fiber wall thickness or radial diameter

(Wheeler et al., 1989; Fichtler and Worbes, 2012; Tarelkin et al., 2016) are difficult to see on fossils and may be masked by poor preservation. The BR specimens are diffuse-porous, whereas some of the BSR specimens are semi-ring porous. All BR specimens have significantly lower vessel frequency (~8-54 mm2) than E. parviareolatum from other sites (56-70 mm2 at BSR and

~100 mm2 at Hays’ Ranch, Kruse, 1954; Boonchai and Manchester, 2012). However, vessel frequency was re-counted using the images of the BSR Edenoxylon parviareolatum and the corresponding scale bar (Boonchai, 2012; Boonchai and Manchester, 2012) with the same

ImageJ approach as the BR specimens and lower numbers that overlapped with the Blue Rim

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material were obtained. Moreover, there can be considerable variation in wood anatomical characters both within species and between sites (Fichtler and Worbes, 2012). Vessel arrangement and diameter is comparable in both the BR and BSR specimens and both have simple perforation plates. Due to the numerous tyloses obscuring end walls, mean vessel element length could only be determined in two BR specimens and the average (~80 and 108 µm) is much shorter than in the BSR specimens (avg. 224 to 362 µm, Boonchai and Manchester, 2012), but within the range of the Hays’ Ranch material (100-300 µm, Kruse, 1954). It is possible that a few of the measurements for vessel element length in the BR specimens are less than the actual length of the vessel element if a tylose mimicked an end wall. The BSR, Hays’ Ranch, and BR specimens all have numerous tyloses and alternate intervessel pits comparable in size (Kruse,

1954; Boonchai and Manchester, 2012). The BR and BSR specimens have similar axial parenchyma patterns, ray width, and black deposits fill the lumina of some of the vessels in

Edenoxylon parviareolatum from both sites (Boonchai and Manchester, 2012). In general, rays without radial canals are shorter in the specimens from Blue Rim. However, rays with radial canals are similar or larger in size in the BR specimens as compared to the BSR Edenoxylon parviareolatum. The BR specimens also have fewer rays per millimeter than the BSR specimens.

The BR, BSR, and Hays’ Ranch specimens all have septate fibers, prismatic crystals in the rays, and share similar ray cellular composition and vessel-ray pitting type (Kruse, 1954; Boonchai and Manchester, 2012).

Kruse’s (1954) specimen of Edenoxylon parviareolatum stem from Hays’ Ranch is slightly different from the Big Sandy Reservoir specimens in that axial parenchyma is rarer and the rays are almost exclusively uniseriate (Boonchai and Manchester, 2012). The mean tangential vessel diameter of 50 µm in Kruse’s specimen is closer to the averages of the BR specimens than

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the BSR material (Kruse, 1954; Boonchai and Manchester, 2012). However, the differences in vessel diameter could relate to plant maturity.

Comparison to other fossil wood of Anacardiaceae. Wood of three species of

Anacardiaceae, Maureroxylon crystalliphorum, Tapirira clarnoensis, and Terrazoxylon ductifera, are documented from the middle Eocene Clarno Nut Beds in Oregon and warrant comparison to the Blue Rim material (Wheeler and Manchester, 2002). All three Clarno species have larger diameter vessels, larger intervessel pits, and longer rays as compared to the Blue Rim specimens. In addition, the Clarno anacardiaceous wood taxa have septate fibers, whereas they are mostly non-septate in the Blue Rim specimens. Maureroxylon crystalliphorum further differs from the BR E. parviareolatum specimens in that it has clearly defined growth rings, wider rays, and radial canals are absent (Wheeler and Manchester, 2002). In contrast, Tapirira clarnoensis and Terrazoxylon ductifera have radial intercellular canals and all three Clarno taxa have tyloses and crystals in common with the Blue Rim material. However, none of the Clarno taxa are similar enough to the BR morphotype to suggest they are the same taxon.

The fossil species, Rhus crystallifera (Anacardiaceae), has been documented from the

Eocene Amethyst Mountain locality in Yellowstone National Park. It differs from the BR

Edenoxylon parviareolatum in having distinct growth rings, semi-ring porosity, vessels mostly solitary with occasional clusters especially in the latewood, larger intervessel pits, and no radial canals (Wheeler et al., 1978).

Boonchai and Manchester (2012) also compared the BSR specimens to other Eocene anacardiaceous woods including Edenoxylon aemulum found in Kent, England (Brett, 1966;

Wheeler and Manchester, 2002). Brett (1966) provided a generic diagnosis for Edenoxylon

(unlike Kruse who had a combined genus and species description), which matches the Blue Rim

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material. Furthermore, Brett (1966) noted Edenoxylon parviareolatum, so named for the small intervessel pits, matches a few extant genera in the tribe Rhoeae including Rhus, Faguetia, and

Trichoscyphya, to which the similarities with the BR material have already been discussed. Most of these fossil anacardiaceous wood species, including the Blue Rim specimens, are diffuse- porous with similar vessel arrangements, heterocellular rays, and simple perforation plates.

However, of the Eocene woods assigned to Anacardiaceae, the BR material is most closely aligned with Edenoxylon parviareolatum.

Family—Indet. Family

Taxon—Incertae sedis Xylotype 1

Specimen—UF 19225-54694 (Figs. 6-9A-C).

Description—Likely diffuse-porous wood with growth rings indistinct or absent. Vessels solitary, in radial multiples of 2 or occasionally 3 or 4 (Fig. 6-9A). Rare clusters of ~3 vessels tangentially arranged. Solitary vessel outline circle to oval. Perforation plates simple. Intervessel pits poorly preserved and challenging to measure, but appear alternate averaging to 5.8 µm (SD

= 1.0 µm, Range: 4.4–7.3 µm, n = 10). Vessel-ray pitting not observed (rays filled with dark deposits). Vessels average 57 µm in tangential diameter (SD = 15 µm, Range: 23–86 µm, n =

24). Transverse view poorly preserved, but vessel frequency averages 14 mm2 (Range: 0–25, n =

6). Some of the vessels in transverse and radial section are filled with black deposits, it is unclear if these are tyloses or other deposits as vessels are not obscured in tangential section. Fibers very thick-walled (Fig. 6-9B). No axial parenchyma observed (but it might be due to the poor preservation). Rays frequently two-seriate, occasionally 1 or 3 cells wide (Fig. 6-9C). Rays vary from exclusively uniseriate, to 1-3 seriate within a ray with varying width, to uniseriate and

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biseriate in the same ray, but the width of the multiseriate portion equals the uniseriate portion.

Rays average 227 µm high (SD = 85 µm, Range: 92–414 µm, n = 30). Ray cellular composition not clear, lots of procumbent cells, possibly all procumbent. Black deposits present in many of the ray cells. Rays closely spaced in tangential section with an average of 22.8 rays per mm

(Range 16–28, n = 10). Rays not storied. No intercellular canals observed.

Remarks—This specimen, Incertae sedis Xylotype 1, is poorly preserved, but does not have the diagnostic characters of any of the taxonomically identified wood types at Blue Rim. However, it is worth comparing to two other unidentified specimens, Incertae sedis Xylotype 2 (UF 18591-

33017) and Incertae sedis Xylotype 3 (UF 19225-57353). Although these three specimens have many anatomical characters in common, differences include the very thick walled fibers in

Incertae sedis Xylotype 1. The intervessel pits in this specimen are not well-preserved and the measurements likely have a larger error than normal, but the average pit size (5.8 µm) is smaller than either Incertae sedis Xylotype 2 (6.8 µm) or Incertae sedis Xylotype 3 (8.7 µm). Whereas ray width is similar among these specimens, Incertae sedis Xylotype 1 often has rays where the uniseriate portion equals the multiseriate portion, which is not as common in the other two specimens. In addition, ray frequency is higher in this specimen, Incertae sedis Xylotype 1.

Taxon—Incertae sedis Xylotype 2

Specimen—UF 18591-33017 (Figs. 6-9D-F)

Description—Growth ring boundaries indistinct to absent (areas with fewer and smaller vessels, but these are not continuous). Wood diffuse-porous with vessels arranged in weak tangential bands and a more defining radial pattern. Vessels solitary and in radial multiples of 2 to 3, rarely

4 or occasional clusters (Fig. 6-9D). Solitary vessels not angular. Perforation plates not observed,

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but likely simple. Intervessel pits alternate (Fig. 6-9E) and small to medium in size with an average of 6.8 µm (SD = 0.4 µm, Range: 6.3–7.5 µm, n = 10). Mean tangential diameter of vessel lumina 75 µm (SD = 29 µm, Range: 29–136 µm, n = 30). Vessel frequency averages 11 mm2 with a range from 6 to 16 (n = 6). Mean vessel element length 169 µm (SD = 62 µm,

Range: 85–337 µm, n = 15). Fibers could not be distinguished from axial parenchyma due to the poor preservation of the specimen (compressed and distorted). Ray start and end points difficult to distinguish, but average 209 µm high (SD = 62 µm, Range: 163–314 µm, n = 19). Rays mostly 1-2 cells wide, occasionally wider, often biseriate. Rays frequent and closely spaced averaging 14 per mm (Range: 10–16, n = 10). Large black spherical structures present in ray cells. Storied structure, intercellular canals and crystals not observed.

Vulnerability Index—Incertae sedis Xylotype 2 has an estimated vulnerability index of 6.8.

Remarks—This specimen (not sure if others too) was described as “Type II” by Manchester and

Wheeler (2006). Incertae sedis Xylotype 2 is poorly preserved, but it lacks the diagnostic features of the previously described Blue Rim woods assigned to Canellaceae, Fabaceae, and

Anacardiaceae. The following characters were entered into InsideWood: 2p, 5p, 13p, 22p, 25p,

41p, 47p, 52p, 97p and modern wood was searched with no mismatches allowed. This recovered

282 results spanning 46 families (InsideWood, 2004-onwards). Despite these results, the characters of this specimen were also compared to those of two other Blue Rim unknowns,

Incertae sedis Xylotype 1 (UF 19225-54694) and Incertae sedis Xylotype 3 (UF 19225-57353).

This specimen, Incertae sedis Xylotype 2, does not have any distinctive characters, but seems more similar to Incertae sedis Xylotype 3 (even though it might have idioblasts in the rays) than

Incertae sedis Xylotype 1 (with its thick walled fibers and higher frequency of rays). Incertae sedis Xylotype 2 has intervessel pits intermediate in size (avg. 6.8 µm) between Incertae sedis

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Xylotype 1 (avg. 5.8 µm) and Incertae sedis Xylotype 3 (avg. 8.7 µm). Vessels size is slightly larger in this specimen as compared to the two from the UF 19225 site. All three Incertae sedis specimens share multiple characters including: absent to indistinct growth rings, diffuse porosity, similar vessel grouping, simple perforation plates, similar vessel diameters and frequency, ray height, and the presence of black structures in the ray cells. However, many of these characters are common across angiosperm woods.

Taxon—Incertae sedis Xylotype 3

Specimen—UF 19225-57353 (Figs. 6-9G-I)

Description—Growth ring boundaries indistinct, possibly defined by irregular areas with no vessels lined with an irregular row of vessels. Wood diffuse-porous with vessels solitary and in radial multiples of 2 or 3, occasionally 4 or 5, or rarely clusters (Fig. 6-9G). Solitary vessels oval to circular in outline; perforation plates likely simple as no scalariform observed. Intervessel pits alternate averaging 8.7 µm in diameter (SD = 0.4 µm, Range: 8.3–9.3 µm, n = 10). Mean tangential diameter of vessel lumina 66 µm (SD = 17 µm, Range: 28–98 µm, n = 30). Vessel frequency averages to 13 mm2 (Range: 8–20, n = 6). Tyloses not obvious in cross section, but some vessels obscured in longitudinal section. Fibers not distinguishable from parenchyma in transverse section. Fibers non-septate, possibly rare septate, but not well preserved. Occasional strands of diffuse apotracheal axial parenchyma observed in tangential section—strand length variable from 2? to 9? cells. Rays mostly 2-seriate, occasionally 3-seriate or uniseriate (Fig. 6-9H

& 6-9I). If uniseriate and biseriate in same ray, uniseriate portion usually narrower than biseriate portion. Rays average 152 µm high (SD = 70 µm, Range: 60–337 µm, n = 30). Ray cellular composition heterocellular, but specific arrangement could not be determined. Rays per mm

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averages to 15 with a range from 12 to 18 (n = 10). Ray cells often with large open lumens and thin walls. Storied structure and intercellular canals not observed. Frequent enlarged white cells in rays—possibly idioblasts. Dark brown to black rounded deposits also present in rays.

Vulnerability Index—This specimen has an estimated V of 5.1.

Remarks—Although specimen UF 19225-57353 was found in vertical position within the UF

19225 leaf quarry (estimated to be ~17 m tall, Table 6-3), poor preservation (most areas are compressed and distorted) did not allow its taxonomic affinities to be determined. However, it does not match with any of the other taxonomically identified angiosperms at Blue Rim. This specimen differs from the BR morphotype of Canellaceae because it has vessels in radial multiples and rays are generally biseriate, rather than uniseriate. Axial parenchyma should be conspicuous if this specimen is aligned with Peltophoroxylon diversiradii. Radial canals and rhomboidal prismatic crystals are diagnostic of Edenoxylon parviareolatum and neither of these characters are present in this specimen.

Many anatomical characters are shared between Incertae sedis Xylotype 1 (UF 19225-

54694), Incertae sedis Xylotype 2 (UF 18591-33017), and this specimen, Incertae sedis Xylotype

3. However, the most notable difference is Incertae sedis Xylotype 3 has larger intervessel pits

(avg. 8.7 µm) than the other Incertae sedis specimens. Strands of axial parenchyma were also observed in this specimen and not in the other two unknowns, but that may be due to variations in preservation. This specimen might have idioblasts in the ray cells, which were not observed in either Incertae sedis Xylotype 1 (UF 19225-54694) or Incertae sedis Xylotype 2 (UF 18591-

33017). Ray frequency was similar between this specimen and Incertae sedis Xylotype 2, but it was higher in Incertae sedis Xylotype 1. Other ray characters including cell composition and

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whether the uniseriate portion was the same width as the multiseriate portion differed between this specimen, Incertae sedis Xylotype 3 and Incertae sedis Xylotype 1.

The characters that could be scored with high confidence (5p, 22p, 26p, 41p, 47p, 97p,

102a, 116p, 118a) were entered into InsideWood (InsideWood, 2004-onwards; Wheeler, 2011) with 0 mismatches and searching only modern wood revealed 93 results in 29 families. Sixteen matches were in the Myrtaceae, whereas 18 results were in the Sapotaceae. When additional characters (2p, 43a, 76p, 92p, 115p) were included and modern wood was searched with 0 mismatches, there were eight results: Guiera senegalensis J.F. Gmel. (Combretaceae), Geissois

(Cunoniaceae), Tamarindus indica L. (Fabaceae, Caesalpinioideae), Henriettella

(Melastomataceae), Eucalyptus dealbata Schauer, E. macrorhyncha F. Muell. ex Benth., and

Syncarpia (Myrtaceae), and Nothofagus subgrp Brassospora (Nothofagaceae, InsideWood,

2004-onwards). These results were reviewed and none were found to be a good match with the fossil.

This wood might not belong to a modern genus, however. The angiosperm megafossil compressions found in the same quarry as this wood specimen were almost exclusively fruits of the extinct sapindalean genus Landeenia (Manchester and Hermsen, 2000) and leaflets called

“Cedrela” schimperi (Meliaceae, MacGinitie, 1974). The association of “C.” schimperi leaves with Landeenia fruits and flowers at Kisinger Lakes (MacGinitie, 1974) and with the same kind of fruits in Paleocene Eocene Thermal Maximum (PETM, ~56 Ma) quarries in the Bighorn

Basin (S.L. Wing and S.R. Manchester, personal communication, 2016) suggest the leaves and fruits represent part of the same extinct plant. Although it cannot be proven because of the lack of a physical connection, the close proximity of these organs around the base of the stem described here leads to the hypothesis that it might represent the wood of Landeenia. If this

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hypothesis is correct, better preserved fossils of this wood type may provide additional characters to resolve the systematic position of Landeenia, whose fruit, flower, and pollen characters are consistent with Sapindales, but not a match to any modern genus (Manchester and Hermsen,

2000).

Taphonomy and Size of Specimens

Some of the fossilized wood samples were found upright and in situ (e.g., Incertae sedis

Xylotype 3, UF 19225-57353) or with minimal transport. However, others appeared to have traveled a more significant distance (e.g., cf. Pinus, UF 19406-61964). An in situ stump (not sampled for wood anatomy due to poor preservation) was ~25 cm in diameter with a lateral root trace extending approximately ~67 cm from the edge of the trunk. The largest fossilized wood piece observed in the field at Blue Rim measured approximately 33 cm in diameter by 42 cm in length. This specimen (not sampled for wood anatomy) was not in situ and appeared to have rolled down one of the badland fingers; it was resting near a gully at the bottom of the escarpment along with many other pieces of petrified wood. The majority of the wood specimens at Blue Rim were prostrate and not in situ. However, some specimens including UF 18591-

33014 through UF 18591-33018, from the 1995 field season were upright. Whereas most of the wood samples suggest relatively small trees or shrubs, a tree over 30 cm in diameter is quite large and suggests larger and/or more mature trees were present on the landscape. Specimens whose full diameter was measured in the field were used to estimate tree height (Table 6-2;

Table 6-3).

Estimated Tree Height. Complete trees are almost never preserved in the fossil record.

However, stumps and logs are more common. The diameter of these tree fragments can be used to estimate tree height (Table 6-2; Table 6-3). McMahon (1973) and McMahon and Kronauer

(1976) used the record trees (largest known individuals) of over 500 North American species to 438

plot height and diameter. They also drew a line representing the buckling height of a hypothetical uniform cylinder with a consistent ratio of E/ρ with E representing the elastic modulus and ρ the mass density. Although McMahon (1973) and McMahon and Kronauer (1976) did have a large dataset, using the record specimen of a species is not a reasonable representative of the average size of that taxon. Record specimens are often found in fields or in areas with optimal growing conditions and little competition. Furthermore, the ratio of E/ρ is not consistent across species.

For these reasons, the values calculated using the work of McMahon (1973) and McMahon and

Kronauer (1976) were excluded from the second average calculation in Table 6-3.

Rich et al. (1986) used a forest of “dicots” and palms from a tropical wet forest in Costa

Rica to measure diameter at breast height and total height. The relationship between diameter and height was plotted for all “dicot” species together and for individual palm and “dicot” species. Rich and colleagues (1986) found diameter varies in relation to height, but they also noted the tallest individuals of a few of the species they examined, exceeded the buckling height as determined in McMahon (1973). This provides additional support for being cautious when using McMahon (1973) and McMahon and Kronauer’s (1976) regression to estimate height.

Brown et al. (1989) developed regression equations (Table 6-2) using height and diameter measurements from ~4,000 trees from 35 sites in Venezuela, Papua New Guinea, and

Puerto Rico. Brown et al. (1989) provided equations for estimating height in both moist and wet life zone conditions (Holdridge, 1967). Holdridge’s (1967) life zone definitions were examined to determine which of the two conditions (moist or wet) were more aligned with the climate conditions inferred for the Blue Rim locality in the early Eocene. The tropical wet life zone has a mean annual precipitation of 400-800 cm and the tropical moist life zone is defined by 200-400 centimeters of mean annual precipitation (Holdridge, 1967). The subtropical wet life zone has a

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mean annual precipitation of 200-800 cm with the subtropical moist life zone mean annual precipitation ranging from 100-200 cm (Holdridge, 1967). Based on this information and the precipitation estimates from Leaf Area Analysis and CLAMP from the leaf fossils at Blue Rim

(S.E. Allen, unpublished data), the moist life zone is more aligned with the conditions at Blue

Rim ~49.0 Ma. Therefore, the regression equation developed from plants growing in moist conditions, rather than wet, was used.

Niklas (1994) also developed correlations between stem length and diameter. Data from

265 self-supporting tree or shrub species from multiple plant clades was used in order to create equations to predict the height of fragmented fossil plants (Niklas, 1994). A subset of these specimens were classified as “woody” and that equation (Table 6-2) was used to estimate the height of the Blue Rim specimens (Table 6-3).

Feldpausch et al. (2011) compiled an extensive database of 39,955 diameter and height measurements of trees from 283 tropical sites in 22 countries. Feldpausch and colleagues (2011) noted numerous factors that impact the height/diameter relationship including forest type and geographic region. Whereas many of the equations presented by Feldpausch et al. (2011) contained variables that could not be calculated with the limited information from fossil logs, an equation detailed in the Appendix of that work removed these coefficients and proved useful for estimating tree height (Table 6-2).

The formulas of Brown et al. (1989), Niklas (1994), and Feldpausch et al. (2011) all give height estimates within 2 meters of each other for an individual stump or log (Table 6-3).

Estimates using the Rich et al. (1986) approach tend to be slightly lower than those three with the

McMahon and McMahon and Kronauer (1973; 1976) estimates being the shortest (Table 6-3).

As previously mentioned, the McMahon (1973; 1976) regression is likely biased (it estimates

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shorter heights using the same diameter) by a dataset based on the largest specimens of a species.

Furthermore, both the Rich et al. (1986) and McMahon and Kronauer (1976) equations were manually calculated from graphs in the original manuscripts. This likely added a small level of additional error not present in the estimates using Brown et al. (1989), Niklas (1994), and

Feldpausch et al. (2011) because those equations were directly provided in the original manuscripts.

Field observations suggest trees were not closely spaced and were generally small, perhaps representing an early successional forest or an environment less favorable to massive trees. However, this assumption does not account for taphonomic effects that may have preferentially preserved smaller woody stems. Alternatively, it could be that wood of the dominant tree type on the landscape, such as Populus, which is well represented in the leaf flora is not preserved because Populus wood decays rapidly and is less likely to enter the fossil record

(Barrett, 1995). Overall, based on the fossils recovered, trees on the Blue Rim landscape ~49.0

Ma were in the vicinity of 28 meters or 92 feet tall (Table 6-3).

Discussion

Anatomy

Most of the Blue Rim woods have features that are common in many extant angiosperm species. Wheeler et al. (2007b) used the InsideWood database (InsideWood, 2004-onwards) to determine that indistinct or absent growth rings, diffuse porosity, exclusively simple perforation plates, alternate intervessel pitting, and non-septate fibers are ubiquitous and occur in at least

75% of the records of modern angiosperms. For these reasons, it is difficult to identify poorly preserved woods with no unusual characters. Specifically, over 90% of the woods coded in

InsideWood are diffuse-porous (InsideWood, 2004-onwards; Wheeler et al., 2007b).

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Density and Specific Gravity

Wood density and wood specific gravity are related, but are not interchangeable terms.

Wood density is the mass of the wood per unit volume—this can be measured at any moisture content (Williamson and Wiemann, 2010). By contrast, wood specific graviy is the density of the wood (using oven dry mass) relative to the density of water (Williamson and Wiemann, 2010).

Wood density can be thought of as a measure of how much of a stem is cell wall versus open space; this is directly connected to plant form and function (Swenson and Enquist, 2007).

Specific gravity was estimated for a few of the well-preserved Blue Rim woods (six specimens assigned to Edenoxylon parviareolatum and Incertae sedis Xylotype 1). Although specific gravity estimates could not be calculated for any of the Peltophoroxylon diversiradii specimens, abundant axial parenchyma (and therefore fewer fibers) frequently correlates with a lower density wood (Zheng and Martínez-Cabrera, 2013). Work on modern floras suggests leaf size decreases with increasing wood density (Chave et al., 2009). Whereas it is not possible to know for sure whether any of the leaf morphotypes at Blue Rim represent the same species as a wood type, Edenoxylon parviareolatum (estimated specific gravity 0.58 to 0.87 using the methods of

Wheeler et al., 2007a) may be aligned with leaves assigned to Rhus nigricans which are on the smaller side.

The specific gravity estimates from Blue Rim (0.58–0.87 using the methods of Wheeler et al., 2007a and 0.82–1.35 using the methods of Martínez-Cabrera et al., 2012) seem high. The average specific gravity of 156 tree species in the United States that comprise over 95% of the total volume of trees is 0.48 (SD = 0.11, Range: 0.29–0.80, Miles and Smith, 2009). The average specific gravity is 0.41 (SD = 0.08, Range: 0.29–0.68) for the 56 species of gymnosperms and

0.52 (SD = 0.10, Range: 0.31–0.80) for the 100 angiosperm species (Miles and Smith, 2009).

These numbers are much lower than specific gravity estimates from the Blue Rim woods, but the 442

values obtained from the fossils are likely inflated due to some of the cells being crushed, lowering the percentage of lumen visible.

Wood density is generally conserved across seed plants (Swenson and Enquist, 2007).

Tropical lowlands, which are dominated by angiosperms, have more variation in wood density than temperate, high elevation, or stressful environments, which are often dominated by gymnosperms (Swenson and Enquist, 2007; Chave et al., 2009). Taxa with low specific gravity wood are likely fast growing, light demanding colonizers or pioneers, whereas taxa with high specific gravity wood are more likely to be shade tolerant, slow growing members of the subcanopy (Wiemann and Williamson, 2002; Baker et al., 2004). Species with intermediate specific gravities are typically mature forest species or emergents.

Some studies have found wood density is positively correlated with climate conditions including mean annual temperature, maximum monthly temperature, and mean annual precipitation (Wiemann and Williamson, 2002; Swenson and Enquist, 2007; Chave et al., 2009).

By contrast, mean specific gravity has been shown to be negatively correlated with soil fertility; sites with higher specific gravity woods had poorer soils (Muller-Landau, 2004). Yet, studies examining the correlation between various environmental conditions and wood density/specific gravity have often contradicted each other; these differences might be due in part to how specific gravity is calculated (Muller-Landau, 2004).

Vulnerability Index

Vulnerability index (V) was also calculated for all Blue Rim wood specimens with both average vessel frequency (mm2) and average tangential vessel diameter (µm, Carlquist, 1975b, a;

Carlquist, 1977; Wheeler, 1991). A low V (below 1) suggests a plant is capable of withstanding freezing or water stress conditions because narrow vessels can withstand lower negative pressures and in plants with high vessel frequency, the effect of each embolism on total 443

conductivity is minimized (Carlquist, 1977, 2012). For example, desert and arctic shrubs have an average V of 0.08 and 0.10, respectively (Carlquist, 1975b, 1977). By contrast, vines and lianas have an average vulnerability index of 8.22 (Carlquist, 1975b, 1977). The Blue Rim woods have vulnerability indices ranging from 1.43 to 10.30 with a median of 3.51 and an average of 4.22

(SD = 2.52, n = 16). Extant tropical trees tend to have high vulnerability indices >2 or 3

(Wheeler, 1991; Burnham and Johnson, 2004). No Blue Rim specimens have a vulnerability index <1, whereas nine specimens have a calculated index >3. All three of the fossil angiosperm wood types identified to family have specimens with values falling into the modern tropical range. The nine specimens with vulnerability indices >3 include four assigned to Edenoxylon parviareolatum, two legumes, the specimen of Canellaceae, Incertae sedis Xylotype 2 (UF

18591-33017) and Incertae sedis Xylotype 3 (UF 19225-57353). In addition, one of the cf.

Edenoxylon parviareolatum specimens (Appendix D) also has a vulnerability index >3. High V values suggest the Blue Rim woods did not experience significant water stress (Wheeler, 1991).

This observation is supported by the local geology. The Bridger Formation in the Blue Rim area

(lower Bridger) preserves fluvial, deltaic, and floodplain environments interbedded with lacustrine sandstones representing transgressions of the Laney Member of the Green River

Formation (M.E. Smith, personal communication, 2014). However, Wheeler (1991) cautions that vulnerability index does not account for the amount of active, conducting sapwood, which can vary greatly.

Ecology and Climate

The Blue Rim wood flora is dominated by angiosperms with only a single Pinaceae sample present. It is suggested that one of the ways angiosperms may have been able to diversify and dominate so many ecosystems, especially in the lowland tropics, is the development of vessels. These structures permit higher maximum conductivity and therefore higher maximum 444

productivity compared to tracheids alone (Chave et al., 2009). Many wood anatomical features, including vessel characters, have been shown to be closely correlated with environmental conditions. Woody species with narrow diameter vessels (<100 µm), a high vessel frequency

(≥40/mm2), and vessels grouped in clusters, features that provide safeguards against embolism, are more common in cool temperate, arctic, tropical montane, alpine, and very dry environments.

By contrast, woody taxa found in frost-free lowland tropical forests often have characters that provide less resistance to hydraulic flow including large diameter vessels (>200 µm), a low vessel frequency (<5/mm2), and simple perforation plates (Baas, 1983; Wheeler and Baas, 1993;

Baas et al., 2004; Ewers et al., 2007; Chave et al., 2009; Carlquist, 2012). Within a genus, generally, the widest vessels are found in species growing in tropical lowlands, the narrowest in species at high latitudes, and intermediate diameter vessels are found in tropical alpine species

(Baas et al., 2004). Many BR specimens are diffuse-porous with narrow (<100µm) vessels. Baas

(2004) noted that diffuse-porosity with narrow vessels is characteristic of evergreen tropical montane, evergreen temperate, and many deciduous temperate trees and shrubs.

Plant size, in addition to environmental factors, also contributes to variations in vessel diameter. For example, very wide vessels are rare in small trees and shrubs (Wheeler and Baas,

1993; Baas et al., 2004; Olson et al., 2014). Many of the BR wood specimens are small hand samples, possibly from plants with a smaller stature, but they could also represent branch rather than trunk wood. This factor could account for the smaller vessel diameters in the Blue Rim woods. Alternatively, it has been shown that trees growing in more stressful environments tend to have significantly smaller vessel diameters than trees growing in less stressful sites (Fichtler and Worbes, 2012).

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Shrubs and branches often have a higher vessel frequency than mature tree trunk wood

(Wheeler and Baas, 1993). In general, Blue Rim woods have an intermediate vessel frequency

(averages range between 7 and 40 per mm2 from 17 specimens), which may indicate they represent mostly branch or shrub wood of tropical lowland species. However, multiple specimens were measured at over one foot in diameter, clearly indicating at least some were trees. One of these specimens (UF 18591-33023; 31 cm) was assigned to Edenoxylon parviareolatum, but most of the other large wood samples documented in the field were too poorly preserved to describe or identify. One exception is Incertae sedis Xylotype 2 (UF 18591-

33017) which had a stem diameter of over 55 cm and was described, but the taxonomic affinity could not be determined.

Conspicuous axial parenchyma patterns including aliform, confluent, and bands more than three cells wide, like those observed in Peltophoroxylon diversiradii, are generally found in tropical, non-drought tolerant taxa (Baas, 1983; Wheeler et al., 2007b; Zheng and Martínez-

Cabrera, 2013). Ample axial parenchyma has been correlated to higher conduction capacity, in part, because axial parenchyma may help prevent cavitation or repair vessels when embolisms occur (Zheng and Martínez-Cabrera, 2013; Morris, 2016; Morris et al., 2016).

Other wood characters also provide ecological and climate signals. For example, growth rings are a consequence of periodic dormancy, a strategy many trees use to withstand conditions including drought, cold, or photoperiodic events and are therefore less common in plants from wet tropical lowlands (Carlquist, 2012). A high percentage of the Blue Rim woods have indistinct growth rings, indicating likely tropical conditions (non-seasonal, equable warm, and wet; Wheeler and Baas, 1993). There are no BR woods with ring-porosity or helical thickenings, characters more common in temperate environments. Randomly arranged vessels is the most

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frequently encountered pattern both globally and in the BR woods; clusters (rare at BR) are less common in the tropics than other environments (Wheeler and Baas, 1993). Crystals (observed in the species of Anacardiaceae and Fabaceae) and silica bodies (possible in Peltophoroxylon diversiradii and a few of the unidentified specimens) are also more common in the tropics than in temperate zones (Wheeler et al., 2007b).

The taxonomically identified woods also provide clues about the climate and ecological conditions at Blue Rim in the latest Early Eocene. For example, legumes have a worldwide distribution, but the Caesalpinioideae are mainly tropical and subtropical woody trees, shrubs, or lianas with species diversity centered in Southeast Asia, Africa, and South America (Klitgård and Lewis, 2010; LPWG, 2013b). Species of extant Peltophorum (a nearest living relative of

Peltophoroxylon) are found in tropical to subtropical climates of the Neotopics, southern Africa, and Austro-Asia; it occupies coastal areas and predominately lowland evergreen and seasonally dry tropical environments (Lewis et al., 2005-onwards; Ramos et al., 2014).

The nearest living relatives of Canellaceae Xylotype 1 are from subtropical and tropical environments. However, both extant and fossil taxa of Canellaceae, including the BR specimen, have scalariform perforation plates. Scalariform perforation plates provide more resistance to hydraulic flow as the end walls of vessel elements account for ~50% of the total resistance in a vessel; they are thought to help localize any air embolisms that might occur (Baas, 1983; Baas et al., 2004; Chave et al., 2009; Carlquist, 2012). The percentage of species with scalariform perforation plates is higher in cool temperate to arctic (23-53%) and tropical high montane (15-

33%) environments, but lower in tropical lowland and arid environments (0-8%, Wheeler and

Baas, 1993). The taxonomic composition of the Blue Rim flora, in conjunction with temperature

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estimates from leaf physiognomic data (S.E. Allen, unpublished data), is more suggestive of tropical montane conditions rather than a cool temperate or arctic environment.

The specimen of Pinaceae is not very informative as pines are distributed from subtropical to temperate areas throughout the Northern Hemisphere and many species are tolerant of extreme conditions including high elevation and/or high latitudes (Farjon and Styles,

1997).

Overall, the wood characters observed at Blue Rim including diffuse-porosity, the absence of distinct growth rings, and rarity of plants with scalariform perforation plates suggest warm to tropical conditions with limited seasonality in southwestern Wyoming in the latest Early

Eocene. This agrees with paleoclimate estimates from leaf physiognomic methods (S.E. Allen, unpublished data) and the presence of frost intolerant taxa like Phoenix windmillis (Allen,

2015a).

Comparison with Other Western Interior North American Eocene Wood Floras

Available data from the limited number of Eocene wood localities studied from the

Western Interior of North America suggest there was variation in taxonomy and wood anatomy across the region (Wheeler and Michalski, 2003). Most early and middle Eocene dicotyledonous woods in the USA lack growth rings (Wheeler, 2001), which is similar to what was observed at

Blue Rim. The BR assemblage is distinctive in some respects. For example, most middle Eocene wood assemblages documented from the USA have a plane-tree relative, Plataninium or

Platanoxylon, and Quercinium (cf. evergreen oaks, Wheeler et al., 1978; Wheeler, 2001;

Gregory et al., 2009). Yet, neither of these taxa are represented at Blue Rim.

Wheeler and Michalski (2003) documented silicified woods from Paleocene and Eocene strata in the Denver Basin of Colorado. Among those, the Eocene sites were dominated by wood of Paraphyllanthoxylon (probable Lauraceae, Wheeler and Michalski, 2003). The characters of 448

the Denver Basin woods, including diffuse porosity (which is shared with the BR woods), are most similar to the wood anatomy of taxa growing in the frost-free lowland tropics today

(Wheeler and Michalski, 2003). However, there is no taxonomic overlap between the identified

Blue Rim and Denver Basin woods.

Although leaf floras from the Eocene of Yellowstone National Park have more angiosperms than conifers, the woods preserve a higher percentage of conifer taxa (Knowlton,

1899; Wheeler et al., 1977; Fritz and Fisk, 1978). The Blue Rim leaf flora is similarly dominated by angiosperms, with a few ferns, and no gymnosperms (Allen, 2015b); however, the wood assemblage differs from that of Yellowstone in having only one coniferous specimen. More than

30 dicotyledonous wood types have been found from the Yellowstone localities of the Lamar

River Formation (Wheeler et al., 1977). Families represented by the wood include: Betulaceae,

Lauraceae, Magnoliaceae, and Platanaceae (Wheeler et al., 1977, 1978). Growth rings in the

Yellowstone woods range from indistinct to distinct (Wheeler et al., 1977, 1978), whereas none of the BR specimens have well-preserved distinct growth rings (however, it is difficult to determine in the Pinaceae specimen). The presence of species in the Yellowstone flora with well- defined growth rings may be due to either its slightly younger age (and therefore further from the peak of early Eocene warming) or the higher elevation of Yellowstone contributed to more seasonality than Blue Rim. Chadwick and Yamamoto (1984) examined 119 wood specimens from the Specimen Creek area of the Gallatin Petrified Forest, Yellowstone National Park,

Montana. They found representatives of three gymnosperm families including Pinaceae and 15 genera in 13 angiosperm families including woods they assigned to Salix (Salicaceae, Yamamoto and Chadwick, 1982; Chadwick and Yamamoto, 1984). The potential presence of wood assignable to Salicaceae is notable because there are definitive leaves and fruits of Populus at

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Blue Rim, but none of the wood specimens seem aligned with this family. Elisabeth Wheeler

(personal communication, 2016) has examined Yamamoto and Chadwick’s original slides from

Specimen Creek, in addition to woods from other areas of Yellowstone, and has not found any evidence of Salix or Populus. Wood of these taxa are not likely to preserve because they tend to decay quickly due to their low specific gravity and extractive content (Elisabeth Wheeler, personal communication, 2016, Barrett, 1995).

The middle Eocene (~44 Ma) wood assemblage from the Clarno Formation in Oregon is extremely diverse with 66 genera. Representatives of Anacardiaceae, Fabaceae, and Pinaceae are present in both the Blue Rim and Clarno floras, but there are no shared species (Wheeler and

Manchester, 2002). The latest Eocene to earliest Oligocene Florissant Fossil Beds National

Monument (~34 Ma) in central Colorado preserves ring-porous woods belonging to the

Ulmaceae, Sapindaceae, and Fabaceae (Wheeler, 2001). This suggests distinct seasonality in the later part of the Eocene as compared to the early Eocene.

Comparison to Other Blue Rim Floral Elements

The wood assemblage, along with the rest of the macroflora from Blue Rim, is dominated by angiosperms. Some taxonomic overlap is evident when comparing the identified woods to the other elements of the macroflora and microflora. The presence of a wood assignable to Pinaceae is significant as no other conifer macrofossils have been recovered from Blue Rim. Coniferous megafossils are also very rare in the adjacent Green River Formation (MacGinitie, 1969; Wilf,

2000). Yet, pollen assignable to Pinaceae (including Pinus) occurs at multiple stratigraphic horizons at Blue Rim, indicating the family was present in the regional flora with possible rare local trees based on the presence of the pinaceous wood specimen. However, the cf. Pinus specimen was found at the bottom of the Blue Rim escarpment, in a gully, with no evidence that it originated nearby. Furthermore, both the hand specimen and microscopic views suggest the cf. 450

Pinus fossil wood was transported from its original growing location and was subjected to compression and distortion during or prior to the permineralization process.

No other macrofossils of Canellaceae have been recovered at Blue Rim to date. However, representatives of Canellaceae might be overlooked in the leaf assemblage because they have evergreen, entire-margined, pinnately veined leaves lacking special characters, which makes them difficult to distinguish from various other entire-margined dicotyledonous taxa. By contrast, the flowers are rather distinctive with 3 sepals, 5 to 12 petals, two to six connate carpels, and six to many stamens fused into a tube (Judd et al., 2008). This combination of characters has not been observed in any of the Blue Rim flower morphotypes.

In addition to the wood, a few legume leaflets have been recovered at Blue Rim. The leaves of this large family are often pinnately compound with entire leaflets and pulvini. There are many (often poorly preserved) laminae with entire margins at Blue Rim. However, only one specimen had an obvious pulvini (which was matched to a few other specimens), allowing for a confident assignment to Fabaceae. Additional specimens could easily represent leaves or leaflets of Fabaceae or other families with entire margins. Legume flowers have not been recognized from Blue Rim, even though there are still multiple unidentified flower morphotypes.

Legumes—both leaves and fruits—are well represented in the nearby Green River flora

(MacGinitie, 1969; Johnson and Plumb, 1995; Grande, 2013) and fruits have also been recovered at the Kisinger Lakes site in northwestern Wyoming.

Along with the anacardiaceous wood, there are also fruits (Pentoperculum) and probable leaves (Rhus nigricans) assigned to Anacardiaceae in the Blue Rim flora (MacGinitie, 1969;

Manchester, 1994; Collinson et al., 2012). Multiple organs assigned to Anacardiaceae provide the potential for whole plant reconstruction.

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In addition, leaves of lianas attributed to “Serjania” in the Sapindaceae and Goweria bluerimensis in the Icacinaceae are present in the macroflora (Allen, 2015b; Allen et al., 2015).

Vitaceae and Icacinaceae (Allen et al., 2015) are also confirmed by fruits and seeds from Blue

Rim; however, no wood of these taxa have been observed.

The Blue Rim flora also has numerous leaves and fruits assignable to Populus, a tree in the Salicaceae. Populus wood should be easily recognizable by its medium to large polygonally shaped alternate intervessel pits and exclusively uniseriate rays with all ray cells procumbent

(Metcalfe and Chalk, 1950; InsideWood, 2004-onwards), but this combination of characters is not present in any of the BR woods. Given the abundance of Populus leaves and fruits at Blue

Rim and other Eocene sites in Wyoming, Utah, and Colorado (MacGinitie, 1969; MacGinitie,

1974), it might seem surprising that wood of Salicaceae have not been recovered. However, this absence might be due to taphonomic bias and the ease with which Populus wood degrades

(Barrett, 1995).

Concluding Remarks

After this survey, only seven different wood types have been recognized from the Blue

Rim localities. Hence, Blue Rim preserves a low diversity wood flora dominated by Edenoxylon parviareolatum (Anacardiaceae). Specimens assigned to Fabaceae, Canellaceae, and Pinaceae are also present, along with a few unidentifiable, but distinct morphotypes. Other elements of the same fossil flora including leaves, reproductive structures, and dispersed pollen and spores suggest overall richness is much higher than is represented by the wood. Stem diameter measurements obtained from some specimens yield tree height estimates of ~16–28 meters. Self- supporting taxa would have been essential for climbers such as Iodes, Vitis, and Lygodium present in the same flora (Manchester and Zavada, 1987; Allen et al., 2015). The angiosperm woods are diffuse-porous with absent or indistinct growth rings and rare scalariform perforation 452

plates. These characters suggest climate conditions were warm with limited seasonality, which agrees with estimates from leaf physiognomic methods (S.E. Allen, unpublished data) and the presence of frost-intolerant taxa like Phoenix windmillis (Allen, 2015a).

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Table 6-1. Comparison of the Blue Rim (Bridger Formation, WY) and Clarno Formation (OR, Wheeler and Manchester, 2002) legumes. Character Peltophoroxylon diversiradii (Bridger Dichrostachyoxylon cf. Euacacioxylon (Clarno cf. Mimosoxylon Formation) herendeenii (Clarno Formation) Formation) (Clarno Formation) Porosity diffuse diffuse diffuse diffuse VD (µm) 45–74 123–186 98–147 162 IP (µm) 5–7 8–10 4–6 10–12 Axial paratracheal: vasicentric, paratracheal: vasicentric, paratracheal: vasicentric, scanty paratracheal to parenchyma aliform, occ. lozenge- aliform, occ. confluent aliform, confluent-banded narrow vasicentric aliform, confluent, occ. banded/marginal bands RH (µm) 189–263 166–259 282–311 476 Ray width 1–2 seriate, rarely larger 1–4 seriate mostly 3–4 seriate 1–4 seriate Ray cellular homocellular procumbent homocellular procumbent OR homocellular procumbent heterocellular with composition OR heterocellular with heterocellular with procumbent OR heterocellular with procumbent body cells procumbent body cells and body cells and 1 or occ. 2 rows procumbent body cells and 1 or occ. 2 rows of 1–3 rows of upright/square of upright/square marginal cells and 1 row of upright/square marginal cells upright/square marginal marginal cells cells Storied absent absent absent absent structure Crystals rare, in chambered axial present, in chambered axial not observed not observed parenchyma parenchyma Note. VD = mean tangential diameter of vessel lumina; IP = intervessel pit size; RH = mean ray height.

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Table 6-2. Equations used to estimate tree height from diameter. Reference Formula Variables Notes McMahon, 1973; log(H) = m(log(D)) m: slope = 2/3; b: m and b calculated from line McMahon and + log(b) OR H = value of H where in fig. 5 of McMahon and Kronauer, 1976 bDm D = 1 = 25 Kronauer, 1976 (page 456) Rich et al., 1986 log(H) = m(log(D)) m: slope = 0.58; b: m and b calculated from line + log(b) OR H = value of y where D in fig. 1 (page 243) bDm = 1 = 33 Brown et al., 1989 H = exp(1.0710 + … Eq. 5 (moist life zone) from 0.5688 ln D*) table 2 (page 886) Niklas, 1994 log(H) = 1.59 + … Eq. “woody” species from 0.39(logD) – table 2 (page 1240) 0.18(logD)2 Feldpausch et al., Ln(H) = β0 + β0 = 1.2229; β1 = Pan tropical eq. from table 2011 β1ln(D*) 0.5320 A2 (page 1100) Note. H = estimated height in meters; D = measured diameter in meters; D* = measured diameter in centimeters.

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Table 6-3. Estimated tree heights of ten Blue Rim fossil wood specimens calculated from the diameter. Estimated height (m) from the five methods in Table 6-2 Blue Rim Diameter Average (SD) specimen (m) A B C D E Average (SD) excluding A FO (7/8/2014) 0.25 9.92 14.77 18.14 19.50 18.83 16.23 (3.97) 17.81 (2.10) FO (7/8/2014) 0.33 11.94 17.35 21.24 22.93 21.82 19.06 (4.50) 20.84 (2.43) UF 18591-33014 0.46 14.90 21.03 25.65 27.42 26.04 23.01 (5.13) 25.04 (2.77) UF 18591-33015 0.31 11.45 16.73 20.50 22.13 21.11 18.39 (4.38) 20.12 (2.36) UF 18591-33016 0.20 8.55 12.98 15.99 16.96 16.72 14.24 (3.56) 15.66 (1.84) UF 18591-33017 0.55 16.78 23.33 28.39 29.96 28.64 25.42 (5.45) 27.58 (2.92) UF 18591-33018 0.25 9.92 14.77 18.14 19.50 18.83 16.23 (3.97) 17.81 (2.10) UF 18591-33022 0.20 8.55 12.98 15.99 16.96 16.72 14.24 (3.56) 15.66 (1.84) UF 18591-33023 0.31 11.45 16.73 20.50 22.13 21.11 18.39 (4.38) 20.12 (2.36) UF 19225-57353 0.23 9.38 14.07 17.31 18.52 18.01 15.46 (3.81) 16.98 (2.00) Note. A = McMahon, 1973; McMahon and Kronauer, 1976; B = Rich et al., 1986; C = Brown et al., 1989; D = Niklas, 1994; E = Feldpausch et al., 2011; SD = standard deviation; FO = field observation.

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Figure 6-1. Location of the Blue Rim site (blue dot) in Sweetwater County in southwestern Wyoming. Thick lines are state boundaries, whereas thin gray lines demarcate county boundaries. Major highways indicated in red for reference.

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Figure 6-2. The wood specimen of Pinaceae, UF 19406-61964. A) Axial resin canals, TS. B) Close-up of tracheids, TS. C & D) Tracheids with large uniseriate pits, RLS. E) Overview of radial section. F) Rays mostly uniseriate, TLS. G) Two larger rays, possibly with remnant resin canals, TLS. H) Ray with likely resin canal, TLS.

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Figure 6-3. Canellaceae Xylotype 1, UF 18591-33036. A) Mostly solitary vessels, TS. B) Tangential lines of crushed cells (darker), TS. C) Part of a scalariform perforation plate and pits of vasicentric tracheids and/or fibers, RLS. D) Radial section overview. E) Scalariform perforation plate and pits of vasicentric tracheids and/or fibers, RLS. F) Close up of pits of vasicentric tracheids and/or fibers, RLS. G) Uniseriate rays, TLS. H) Mostly intact scalariform perforation plate, TLS. I) Close up of scalariform perforation plate, TLS.

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Figure 6-4. Specimens assigned to Peltophoroxylon diversiradii (Caesalpinioideae, Fabaceae). A) UF 19338W-61965, Vasicentric and banded axial parenchyma, TS. B) UF 19338W-61966, Vessels grouped in short radial multiples, occasional clusters or solitary, TS. C) UF 19338W-61965, Prominent rays and vessels in radial multiples surrounded by axial parenchyma, TS. D & E) UF 19338W-61966; D) Radial section overview. E) Parenchyma clearly visible adjacent to the vessel, RLS. F & G) UF 19338W-61965; F) Overview of tangential section. G) Close-up of mostly biseriate rays, TLS. H & I) UF 19338W-61966; H) Parenchyma surrounding vessel, TLS. I) Alternate intervessel pits, TLS.

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Figure 6-5. Specimens assigned to Peltophoroxylon diversiradii (Caesalpinioideae, Fabaceae). A & B) UF 18591-33042; A) Banded and marginal parenchyma, TS. B) Rays and vessels with intervessel pits, TLS. C-E) UF 15761-56323; C) Overview of radial section. D) Vessel-ray pits, RLS. E) Intervessel pits, RLS.

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Figure 6-6. A well-preserved specimen of Edenoxylon parviareolatum (Anacardiaceae), UF 00341S-61961. A) Vessels grouped in radial multiples and solitary, TS. B) Overview of radial section. C) Close-up of vessels and fibers, RLS. D) Numerous prismatic crystals in ray, RLS. E) Intervessel pits and crystals in the adjacent ray cells, TLS. F) Vessel elements with alternate intervessel pits interspersed between rays with prismatic crystals, TLS. G) Ray with well-defined radial canal, TLS. H) Broader view of tangential section.

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Figure 6-7. Views of other specimens assigned to Edenoxylon parviareolatum. A) UF 18591- 33008, Transverse section overview. B) UF 18289-56308, Tyloses present in the vessels, TS. C) UF 18591-33008, Close-up of fiber cells, TS. D) UF 18289-56308, Tangential section overview with radial canals. E) UF 18591-33008, Multiseriate ray with radial canal. Ray to the lower right has a prismatic crystal, TLS. F & G) UF 18289-56305; F) Ray cells with prismatic crystals, RLS. G) Oblong rounded to horizontal (gash-like) vessel-ray pitting, RLS. H) UF 18289-56306, Septate fibers, RLS.

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Figure 6-8. Additional views of Edenoxylon parviareolatum. A-D) UF 18591-33023; A) Close- up of fibers and prismatic crystals in ray cells, TS. B) Radial canals, TLS. C) Ray with single radial canal, TLS. D) Ray with two radial canals, TLS. E) UF 18591- 33030, Double radial canal and vessel elements, TLS. F) UF 18591-33034, Multiseriate ray with canal, TLS. G-J) UF 18591-33021; G) Radial canal in long ray, TLS. H) Overview of tangential section dominated by regular rays without canals. I) Prismatic crystal in ray cell adjacent to a vessel, TLS. J) Rays with prismatic crystals, TLS.

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Figure 6-9. The Incertae sedis specimens. A-C) Incertae sedis Xylotype 1, UF 19225-54694; A) Vessels generally grouped in short radial multiples, TS. B) Very thick-walled fibers, TS. C) Biseriate rays, TLS. D-F) Incertae sedis Xylotype 2, UF 18591-33017; D) Vessels grouped in radial multiples, clusters, or solitary, TS. E) Alternate intervessel pits, TLS. F) Rays and vessels, TLS. G-I) Incertae sedis Xylotype 3, UF 19225- 57353; G) Vessels solitary, grouped in short radial multiples, or occasionally clusters, TS. H) Rays often biseriate; enlarged white cells may represent idioblasts, TLS; I) Medium-sized, alternate intervessel pits and close-up of rays, TLS.

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CHAPTER 7 FLORAL OVERVIEW, PALEOCLIMATE, AND PALEOECOLOGY OF BLUE RIM WITH A COMPARISION TO OTHER EARLY EOCENE SITES FROM WESTERN NORTH AMERICA

Part I: Blue Rim Flora

The Blue Rim flora is unusual in that all plant organs are present. Each organ preserves a different species richness and taxonomic composition. There are at least 69 leaf types among the three horizons at Blue Rim with each horizon having over 60% unique morphotypes. Most of the reproductive structures were recovered in the lower horizon, with only a few in the upper horizon and none in the isolated channel fill (UF 19404, stratigraphically oldest). Of the macrofossils, the wood had the lowest species richness with only seven recognizable types. Taxonomically, the

Blue Rim macroflora includes at least 19 angiosperm families, one gymnosperm family

(Pinaceae), and a few monilophytes. Anacardiaceae (leaves, fruits, and wood) and Salicaceae

(leaves, fruits, and flowers) are each represented by three plant parts, whereas Platanaceae

(leaves and fruits), Icacinaceae (leaves and fruits), Fabaceae (leaves and wood), and Arecaceae

(rare leaf fragments and flowers) are each represented by two plant parts. In addition, the abundant climbing fern, Lygodium kaufussi, is represented by dispersed spores and both sterile leaves and branched fertile foliage with sorophores.

The microflora adds to the overall taxonomic diversity at Blue Rim with grains likely representative of: Ephedraceae, Cupressaceae, Amaranthaceae, Betulaceae, Juglandaceae, and

Asteraceae. These families, not otherwise recognized in the macroflora (possible juglandaceous leaflets present), include taxa that prefer drier and or cooler environments, so their pollen grains were probably carried in from the surrounding highlands.

Many leaves and reproductive structures from Blue Rim, even those with distinctive characters, have not been identified. Often, the combination of characters does not fit cleanly

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into a modern clade or the characters are convergent in more than one taxonomic group. Whereas similar leaf morphology can be observed between unrelated groups today, reproductive structures are usually more distinctive and often have the synapomorphy or synapomorphies for the clade. Yet, many of the flowers and inflorescences at Blue Rim do not seem to fit with a modern group and are likely representative of extinct genera. For example, possible taxonomic affinities for the “Poofball” morphotype were explored, especially after successful extraction of the in situ pollen, but its nearest living relative within the Poales remains elusive.

Both the UF 19404 quarry (stratigraphically oldest) and the upper horizon flora

(stratigraphically youngest) are more diverse than the lower horizon, despite more intensive collecting at the lower horizon. This difference is likely a direct reflection of both the depositional environment and an accumulation of leaves from a wider geographical area, rather than a representation of what was just growing locally. The flora from the lower horizon quarries, especially UF 15761, was deposited in a calmer environment based on the smaller grain size of the sediment, its better preservation, and the presence of delicate structures including flowers with intact stamens and in situ pollen. Floristic composition and species richness is strongly dependent on the depositional environment and floras are most similar between deposits representing flood basins due to the larger area from which plants are derived (Burnham, 1994a;

Wing and Dimichele, 1995). Furthermore, a small sampling scale in paleontology can lead to the false impression that samples are heterogeneous (Burnham, 1994a).

In general, macrofossils, like leaves, do not hold up when they are transported long distances, so well-preserved fossils represent a very local flora (Coiffard et al., 2006). In contrast, micro-fossils like pollen and spores can be carried in the wind and water for many kilometers, be deposited, and remain in good condition. Thus, a micro-flora represents a wider

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regional flora, but is often biased toward wind-dispersed taxa. In addition, there is often a strong taxonomic bias in both macro and micro-floras. It has been observed that some families and specific plant parts just do not preserve well (Burnham, 1994a; Burnham and Johnson, 2004).

Differential taphonomic effects can also alter the relative abundances of the taxa recovered as fossils relative to their original abundance in the living vegetation.

Modern forest litter has been used as a basis to reconstruct fossil forests. Extensive work has shown that the extent to which forest litter approaches the true diversity of a forest is affected by factors such as growth strategy, physiology, and likelihood of preservation (Burnham et al.,

1992; DiMichele and Gastaldo, 2008). However, DiMichele and Gastaldo (2008) note that as plant parts are disarticulated and deposited, some taxa are inherently overrepresented, while others are underrepresented. For example, a large deciduous tree or a single species stand of deciduous trees will significantly contribute to the leaf litter and thus have a higher chance of being fossilized (Burnham et al., 1992; Burnham and Johnson, 2004).

Part II: Paleoclimate and Paleoecology of Blue Rim

Plant fossils can be used as a tool to reconstruct past climate. Although climate fluctuates, morphological traits adapted to specific conditions are thought to be relatively stable through time and can be used to estimate the environmental conditions in the past (Wing and Greenwood,

1993). One of the methods in use since the early days of paleobotany relies on identifying a fossil and applying the climate parameters of that plant’s closest extant relative. Today, this method is termed the Nearest Living Relative (NLR) approach. As early as the mid-1800s, paleobotanists realized that climate might influence morphological traits. This relationship was quantified for leaf physiognomy in extant forests by Bailey and Sinnott (Bailey and Sinnott,

1915, 1916) and later expanded with the development of the Climate Leaf Analysis Multivariate

Program (CLAMP, Wolfe, 1993) and Leaf Margin Analysis (LMA, Wilf, 1997). 473

The main function of a leaf is to maximize photosynthetic rate in its environment (Wolfe and Spicer, 1999). Because leaves are the primary photosynthetic organs on a plant, they must adapt to environmental conditions quickly and sensitively, hence leaf physiognomic methods provide an effective way to infer paleoclimate (Wing and Greenwood, 1993; Traiser et al., 2005;

Uhl, 2006). Efficient leaves maximize surface area and minimize water loss and energy input

(Wolfe and Spicer, 1999). Photosynthetic rate in plants is strongly correlated with both temperature and water availability (Rees and Ziegler, 1999). Leaf size and shape, two quantifiable traits that are good indicators of paleoclimate, are influenced by moisture, temperature, and light levels (Wing and Greenwood, 1993; Wilf et al., 1998a). Plants in varying geographic locations with approximately the same climate and environmental conditions typically have similar leaf morphologies (Wolfe and Spicer, 1999). Furthermore, leaf physiognomic traits vary predictably along climatic and environmental gradients (Traiser et al.,

2005). Extant vegetation is correlated to climate (especially precipitation and temperature) worldwide and these relationships seem to be consistent through time (Rees and Ziegler, 1999).

Non-monocot angiosperms (commonly referred to as “dicots”) have a diverse suite of leaf anatomical characters that can be correlated to their environment (Wolfe and Spicer, 1999).

Woody angiosperms, rather than herbaceous plants, are used because they live longer and it is hypothesized that their leaf physiognomy is a more accurate representation of climate over a larger geographic area (Traiser et al., 2005). The leaf physiognomy-climate relationship is best understood for angiosperms, but non-angiosperms also show patterns that can be correlated with climate (Uhl and Mosbrugger, 1999). For example, the leaf physiognomic approaches are used to analyze angiosperms, whereas non-angiosperms or other plant organs can be studied with the

Nearest Living Relative (NLR) and Coexistence Approaches (CA, Mosbrugger and Utescher,

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1997; Mosbrugger, 1999; Rees and Ziegler, 1999; Uhl, 2006). Below, I detail and discuss the specific paleoclimate methods I applied to the Blue Rim leaf flora.

Paleoclimate methods overview. The univariate Leaf Margin Analysis (LMA) uses the known correlation between mean annual temperature (MAT) and the percentage of untoothed margined species in a local flora. Wing and Greenwood (1993) expanded this method based on earlier work by J.A. Wolfe (1979) and it was later revised by Wilf (1997). More recently, researchers have developed updated equations that include larger modern datasets or that take into account the depositional environments from which fossils are most likely to be recovered

(Kowalski and Dilcher, 2003; Miller et al., 2006; Peppe et al., 2011).

The univariate Leaf Area Analysis (LAA) was developed by Wilf and colleagues (1998a) who found that multivariate approaches, like CLAMP (discussed below), often overestimated precipitation levels. Paleoprecipitation estimates from multiple floras using both univariate and multivariate methods were analyzed to reach this conclusion (Wilf et al., 1998a). Wilf et al.

(1998a) demonstrated a clear correlation between mean leaf area and annual precipitation. One of the many functions of a leaf is to transpire water into the atmosphere, so leaves have a high surface area to volume ratio to allow for gas exchange. Therefore, plants in drier climates tend to have smaller leaves because they cannot afford to transpire as much water (Wilf et al., 1998a).

However, the fossil record is somewhat biased because large leaves are often not preserved, or only present in small fragments (Wilf et al., 1998a; Spicer, 2000; Merkhofer et al., 2015).

Methods, including vein scaling, have been developed to estimate the area of fragmented leaves by measuring the density of secondary veins (Sack et al., 2012; Merkhofer et al., 2015).

Although this method is beneficial to expand the size range of a morphotype if the larger specimens of that morphotype are fragmented, it is time consuming and can estimate erroneous

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areas (e.g., smaller than the original fragment or significantly overestimated, Merkhofer et al.,

2015). Vein scaling also produces a broader range of estimated area compared to other area measurement methods (Merkhofer et al., 2015). Other digital methods have been developed to measure continuous leaf physiognomic characters including laminar area, laminar shape, tooth size, tooth frequency, and tooth area (Huff et al., 2003; Royer et al., 2005; Peppe et al., 2010;

Peppe et al., 2011). However, they were not applied to the Blue Rim flora because whereas these characters have demonstrated a clear climate signal (e.g., leaves of the same species may have fewer teeth when grown in a warm environment), they are time consuming to measure and have only produced slightly improved (e.g., <1 °C warmer) temperature estimates with slightly smaller errors (e.g., ± 4 vs. 5 °C, Peppe et al., 2010; Peppe et al., 2011; Royer, 2012).

The multivariate Climate Leaf Analysis Multivariate Program (CLAMP) was developed by Jack Wolfe (1993) and has since been expanded numerous times (e.g., Spicer et al., 2009).

Modern leaves from woody dicotyledons are collected and scored for 31 morphological characters for each collection site. Scored floras from around the world are added to a database with their known climate parameters either from nearby meteorological stations or a global gridded model (Wolfe, 1993; Wolfe and Spicer, 1999; Spicer et al., 2009).

When a fossil flora is scored, it is added to the database and the characters are ordinated in multivariate space and compared to the modern floras and their corresponding climate parameters using Canonical Correspondence Analysis (CCA). Leaves from at least 20 species of woody dicots are required, although 30 or more are recommended to increase accuracy (Wolfe,

1993; Wolfe and Spicer, 1999). CCA, which does not require variables to be independent or normally distributed (Kovach and Spicer, 1996; Spicer, 2000), is a good tool because paleontology often has missing or skewed data, but the results are not greatly affected (Wolfe,

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1993; Spicer et al., 2011). CLAMP estimates eleven climate parameters. The relationship between climate and leaf physiognomic characters is usually nonlinear, which contrasts with

LMA and makes this multivariate approach more appropriate (Wolfe, 1993; Wolfe and Spicer,

1999). CLAMP is thought to be accurate for estimating paleoclimate for the last 100-120 million years for floras in terrestrial environments (Wolfe, 1994; Rees and Ziegler, 1999).

CLAMP has several drawbacks. It is biased towards the northern hemisphere, where most of the modern samples have been collected, although more southern hemisphere data are being added (Wolfe and Spicer, 1999; Spicer et al., 2009). Wolfe and Spicer (1999) also noted that taphonomic distortions of the fossil assemblage may falsely alter the character scoring and the subsequent climate estimates; however, when characters were removed after modern floras were scored (mimicking missing data in a fossil assemblage) the results were within the margin of error as compared to when the dataset was complete (Spicer et al., 2011). Compared to NLR,

CLAMP is thought to be accurate, precise, and repeatable (Wolfe, 1994) because it is quantitative rather than qualitative, but various studies (e.g., Little et al., 2010) have questioned these claims. Many have argued that if so much variation in leaf physiognomy is explained by temperature and precipitation, then the simpler univariate LMA and LAA methods should be used. However, the multivariate approach was stressed because species from the same geographical location and environment might have significantly different traits and these variations would be lost by only examining a single-character (Wolfe, 1993). Furthermore, some have commented that a CLAMP analysis is not easily duplicated because morphotypes are rarely identified and scored identically by additional researchers (Wolfe, 1993, 1994).

Peppe et al. (2010) note that CLAMP does not have size categories for large leaves, and mean leaf area for a site is often underestimated as compared to when leaf measurements are

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used directly rather than binning to size categories. This increases the error for climate estimates relating to moisture; for example, growing season precipitation and related climate variables were usually higher when actual leaf sizes were used as opposed to the same leaves using the

CLAMP size template (Peppe et al., 2010). In contrast, Wilf et al. (1998a) noted that CLAMP tends to overestimate precipitation values. It should be noted that Wolfe (1993) made his own leaf size categories for CLAMP after observing that many leaves were intermediate in size between the commonly used Raunkiar-Webb size classes.

Paleoclimate methods discussion. Each of the above approaches has been criticized, but general limitations apply to both the leaf physiognomic and taxonomic paleoclimate methods. A common problem is that errors can occur when one separates the leaves of a fossil flora into species or morphotypes (Wing and Greenwood, 1993). Moreover, many morphotypes in a fossil flora are only represented by a single specimen and there is debate as to whether these examples should be included in a NLR or CA analysis because the probability of mis-identifying a taxon based on one specimen is high (Burnham, 1994a; Wilf et al., 1998b). Many of the Blue Rim morphotypes are only recognized based on one or a few fossils. For example, if one splits a group of entire-margined leaves into four morphotypes when they really represent variants of a single species, the resulting temperature estimates would be artificially inflated.

Floral composition can change with variations in stratigraphy or lithology, which may not accurately represent true variations in the regional flora (Wing, 1998b). It has been found that paleoclimate/ecological estimates (leaf physiognomic or taxonomic) of a flora are strongly biased, based on the sedimentological facies in which it is preserved (e.g., lacustrine, channel- margin, floodbasin, Burnham, 1994a; Wing, 1998b). Floodbasin, rather than channel or channel margin floras are species rich and provide the most accurate representation of the regional flora

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and climate. Because of this factor, Burnham (1994a) commented that one should only compare floras from similar depositional environments and paleoenvironment should be assessed independent of plant composition (Burnham, 1994a; Wing, 1998b). Depositional environment can also bias the type of plant preserved. For example, on the edge of a lake, one would expect to find taxa that prefer and can tolerate a high water table (MacGinitie, 1969).

The results of leaf physiognomic analyses could be affected by various factors including taphonomic effects or preservational distortion (Uhl, 2006). Furthermore, the climate correlation may differ both between specialized habitats within a larger region and between different regions worldwide (Uhl, 2006). Low specimen numbers or low diversity is problematic for univariate methods like LMA, but less so with multivariate approaches like CLAMP in the opinion of Uhl

(2006). The best fossil floras for a leaf physiognomic climate analysis are large and diverse (Uhl,

2006). Leaf physiognomic methods, including LMA and CLAMP, often underestimate MAT as compared to NLR or other non-physionomic approaches because fossil floras are often from wet areas that tend to have a higher percentage of toothed margined leaves (Kowalski and Dilcher,

2003; Spicer et al., 2011; Royer et al., 2012). Wet sites with shallow water tables can have 10-

15% more species with teeth which can result an underestimate of temperature by 4 °C or more

(Peppe et al., 2011). Using extant datasets from wet environments can help compensate for this problem (to avoid artifically low estimated MAT) because the majority of preserved fossil floras grew near and were deposited in terrestrial aquatic systems (Kowalski and Dilcher, 2003; Uhl et al., 2007; Royer et al., 2012).

Most datasets of modern climate parameters and leaf measurements are flawed because not every climate and habitat in the world has been thoroughly sampled and weather stations are often near populated areas where the vegetation is more likely to be disturbed or unnatural

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(Wing, 1987; Wilf et al., 1998b). Furthermore, many past climates are not represented in the modern world and plants from millions of years ago may be extinct, making it difficult to compare them to modern taxa (Wing, 1987; Wilf et al., 1998b).

The lack of phylogenetic information in the leaf physiognomic-based paleoclimate methods has also been criticized. Little et al. (2010) found that whereas many leaf traits do adapt to climate conditions, including temperature, the presence or absence of teeth—a key trait in both

LMA and CLAMP for estimating paleotemperature—has a strong phylogenetic signal and only a very weak adaptive signal. Some clades are always toothed, whereas others are always untoothed regardless of where they are growing (Little et al., 2010). Proponents of digital leaf physiognomy emphasize that examining continuous characters (e.g., frequency of teeth) versus binary (e.g., presence or absence of teeth) can help overcome this issue (Royer, 2012).

Paleoecology. Leaf thickness, quantified as mass per area (MA) has been correlated to ecological traits including photosynthetic rate, leaf life span, nutrient concentration, and resistance to herbivores (Royer et al., 2007; Royer et al., 2010). There is a continuum of MA that represents maximum retention of resources to rapid acquisition of resources (Royer et al., 2007;

Royer et al., 2010). Resource retaining taxa (e.g., evergreen) tend to have thicker leaves (high

MA) which is correlated to a higher initial investment in leaves, lower photosynthetic rates, longer leaf life span, lower nitrogen and phosphorous concentrations, and an increased defense against herbivores due to thicker and/or tougher leaves (Royer et al., 2007; Royer et al., 2010).

Royer et al. (2007) used a dataset of 667 modern species at 65 sites to create the MA continuum.

MA can be estimated from fossil leaves using petiole width and leaf area (Royer et al., 2007;

Royer et al., 2010). This method is very useful for estimating MA for fossil leaves, because the thickness of the leaf will have been distorted by compaction, but the petiole width can be readily

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measured. Fossil leaves without intact petioles or whose area cannot be determined with a minimal amount of uncertainty must be excluded when this method is applied. Taphonomic processes can also slightly increase or decrease original leaf and petiole sizes (Royer et al.,

2007), so calculated leaf mass per areas from fossils represent estimates. Furthermore, evidence of insect herbivory can be analyzed on leaves and compared with MA estimates to see if the correlation of higher MA to lower rates of herbivory remains intact in the fossil record (Royer et al., 2007). Whereas MA can be measured from other non-angiosperm plant groups today, so far, the correlation for fossils has only been determined for woody dicotyledonous taxa.

In the following section, I apply the leaf physiognomic methods described above, including LMA, LAA, CLAMP, and MA to the three leaf horizons investigated at Blue Rim.

UF 19404: Isolated Channel Fill

The 19404 channel fill quarry preserves 28 leaf morphotypes: fourteen toothed (10 based on single specimens) and fourteen untoothed (7 based on single specimens). However, a few toothed morphotypes, represented by single specimens, may be parts of large leaves of

Macginitiea. If another researcher were to lump those morphotypes with Macginitiea or if any of the other morphotype assignments were altered, the temperature estimates would change accordingly. Additional future collecting might provide more insights of where to set the limits of variation among morphotypes.

Mean annual temperature (MAT) was calculated using univariate leaf margin analysis

(LMA). Five different equations to calculate MAT were applied using the percentage of untoothed morphotypes (0.50%). These equations and results are presented in Table 7-1. MAT estimates ranged from ~15 to 20 °C (~59 to 68 °F) with an average of 16.8 °C. A rough estimate for precipitation for the UF 19404 site was produced using leaf area analysis (LAA, Table 7-2).

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These estimates were obtained by using the largest Raunkiaer-Webb category represented by the morphotype (taken from the written description). This is similar to column “B” from the lower horizon (Table 7-4). The errors on the precipitation estimates should be considered minima because many of the morphotypes were represented by a single, partial specimen making it difficult to estimate the original leaf size.

The coarse sediment, higher diversity (than the lower horizon), and fragmentary nature of the leaves indicates a channel fill (or similar allochthonous) depositional environment. A

CLAMP analysis was not completed for the UF 19404 quarry due to the high percentage of leaves without intact apices, bases, shapes, or sizes—all important characters in a CLAMP analysis. Leaf mass per area (MA) could not be completed on this collection either as very few specimens have a complete area and an intact petiole.

Lower Horizon

Both univariate and multivariate approaches were used to estimate the temperature and precipitation using the leaves from the lower horizon at Blue Rim.

Leaf Margin Analysis (LMA). Of the twenty morphotypes in the lower horizon of Blue

Rim, 11 were toothed and 9 were untoothed. Therefore P (percent entire-margined species) =

0.45, for the 45% of the morphotypes that are entire. Five different LMA equations to calculate

MAT were applied using the percentage of untoothed morphotypes. These equations and results are presented in Table 7-3. MAT estimates ranged from 13.8 to 18.6 °C (~57–65 °F) with an average of 15.3 °C.

Leaf Area Analysis (LAA). The univariate leaf area analysis (LAA) was performed to estimated mean annual precipitation (MAP). This method is based on the fact that wetter climates tend to have larger leaves. Two approaches were used. The first was the traditional

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method that used the average leaf size of the morphotype (column A in Table 7-4), whereas the second approach used the largest Raunkiaer-Webb category the leaf morphotype fell into

(column B in Table 7-4). This alternative approach was included because fossil floras tend to be biased toward smaller leaves. Four different regression equations were used to estimate MAP because they are all based on different regions of the world today.

Climate Leaf Analysis Multivariate Program (CLAMP). The lower horizon leaves were scored (see Appendix E) for the 31 characters following the CLAMP character definitions

(available at http://clamp.ibcas.ac.cn/). The analysis was also performed using the online tool

(http://clamp.ibcas.ac.cn/CLAMP_Run_Analysis.html). I used the Physg3brcAZ dataset with

144 modern vegetation sites because that database is thought to be good for non-monsoonal, warm (>0 °C) localities. Since the Physg3brcAZ dataset has mostly mid to high latitude sites and few low latitude sites, Spicer et al. (2009) added an alternative method using a global gridded model of meteorological data to try to overcome that shortcoming. When tested, the results using the two approaches (new global gridded model and original climate stations) were indistinguishable (Spicer et al., 2009). The results from Blue Rim using both meteorological datasets were similar with the global gridded model estimating slightly cooler and drier conditions than the nearby meteorological stations database (Table 7-5).

Although the Blue Rim lower horizon flora barely meets the minimum recommended number of morphotypes (20) for the temperature estimates, the precipitation estimates are known to be less accurate when fewer than 25 morphotypes are available (Wolfe, 1993; Wolfe and

Spicer, 1999; Spicer, 2007; Spicer et al., 2009). Therefore the errors on the precipitation estimates should be considered minima. This may explain why the precipitation estimates using

CLAMP are considerably higher than the univariate LAA. In addition, Wilf et al. (1998a) found

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that CLAMP overestimated precipitation significantly (often more than double) by applying the

CLAMP analysis to seven extant floras. The Blue Rim flora fell within the physiognomic space

(i.e., within the range of the extant floras in the database) using both types of meteorological data

(local climate stations and global gridded) and the completeness score of 1 is well above the recommended minimum of 0.66 (Spicer et al., 2011).

The CLAMP mean annual temperature estimates (Table 7-5) are similar to the values for modern day Jerome, AZ (Jerome is in central AZ to the southwest of Flagstaff). The growing season precipitation (GSP, similar to MAP in the univariate approaches) estimates are similar to modern day Puerto Rico. The cold month mean temperature (CMMT) estimates are well above freezing, which indicates little or no frost. This is also supported by frost intolerant taxa present at Blue Rim including Phoenix windmillis (Allen, 2015a). Taken together, the temperature and precipitation estimates from the CLAMP analysis indicate a wet, slightly cooler subtropical climate with distinct, but moderate seasonality (both in temperature and precipitation). In the

USA, these conditions are similar to, but warmer than (Blue Rim has a warmer CMMT) the western side (windward, wetter side) of the southern Appalachians (Georgia and Tennessee) today at low to mid elevations. Today, these areas are classified as warm temperate, fully humid, with hot summers (Cfa) according to the Köppen-Geiger climate system (Kottek et al., 2006).

Minimum temperatures are between -3 °C and 18 °C, whereas the maximum temperatures are

≥22 °C in an area with a Cfa designation (Kottek et al., 2006)

Early Eocene reptiles from Wyoming indicate that the CMMT estimated using CLAMP may be too cold. The presence of turtle fossils in northern Wyoming during the Eocene suggests cold month mean temperatures above 13 ºC (Wing and Greenwood, 1993). Large crocodile and small lizard fossils at high latitudes in Wyoming suggest rare to no frost. Furthermore, mammal

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taxa found in Eocene sediments of Wyoming require year-round food sources that would not have been available in seasonally cold climates (Wing and Greenwood, 1993).

Paleoecology results. A Leaf Mass per Area (MA) analysis was completed for 14 of the

20 leaf morphotypes from the lower horizon (Table 7-6). This was done following the methods outlined in Royer et al (2007) by measuring the petiole width (mm) and leaf area (mm2) using

ImageJ (Rasband, 1997-onwards). The measurements of petiole width (PW) and area (A) were

2 used to calculate MA using the following equation: logMA = 3.070 + 0.382 x log(PW /A) (Royer et al., 2007). Six of the Blue Rim lower level leaf morphotypes suggested a leaf lifespan of <1 year and were likely deciduous, while eight others suggested a leaf lifespan of ~1 year (Table 7-

6). However, three of the 14 morphotypes were based only on the measurements from one specimen and the blade area may have been slightly underestimated (e.g., morphotype TT) or it was challenging to determine the width of the petiole (e.g., morphotype ATR). The range of MA was 70.2 – 127.1 g/m2 with an average of 92.5 g/m2.

It has been shown that plants with toothed leaves are more likely to be deciduous, and tend to have thin leaves with low leaf mass per area and high levels of nitrogen, independent of temperature (Royer et al., 2012). Of the six Blue Rim morphotypes with estimated leaf life spans

<1 year, four are toothed (Table 7-6), but this may be a reflection of having more toothed than untoothed morphotypes in the lower horizon and more of the toothed types were complete enough to evaluate for MA as compared to the untoothed morphotypes.

In comparing the Blue Rim results (Fig. 7-1) to Figure 3 (on page 443) of Royer et al.

(2010), two of the five habitat and climate options are not a match. Royer et al. (2010) compiled

MA data from 5 extant sites representing: 1. riparian, cold temperate; 2. riparian, warm temperate;

3. nonriparian, warm temperate; 4. nonriparian, seasonally dry tropics; and 5. nonriparian, wet

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tropics. The Blue Rim results do not match with either 1. riparian, cold temperate or 5. nonriparian, wet tropics. Riparian, warm temperate has the highest percentage of species in the

2 2 51 to 75 g/m bin with the highest MA values falling in the 101 to 125 g/m bin. Nonriparian, warm temperate has the highest percentage of species in the 76 to 100 g/m2 bin with the highest

2 values falling in the 151 to 175 g/m bin. Finally, the MA results for the nonriparian, seasonally

2 dry tropics locality had a peak MA in the 51 to 75 g/m bin with values extending to the 151 to

175 g/m2 bin (Royer et al., 2010). In contrast, Blue Rim has the highest percentage of species in the 76 to 100 g/m2 bin with values extending to the 126 to 150 g/m2 bin. It is unclear whether a riparian or nonriparian environment is a closer match to the Blue Rim results, but the estimated

MA from the fossils does fit well within the range of modern warm temperate conditions.

Upper Horizon

The upper horizon (including the quarries UF 00341, 19405, 19296, and 19297) preserves 36 leaf morphotypes; 21 toothed (8 based on single specimens) and 15 untoothed (5 based on single specimens. Some of the specimens were challenging to sort into morphotypes and if another researcher arrived at a different number of toothed vs. untoothed morphotypes the resulting temperature estimates would change.

Mean annual temperature (MAT) was calculated using univariate leaf margin analysis

(LMA). Five different equations to calculate MAT were applied using the percentage of untoothed morphotypes (0.42%). These equations and results are presented in Table 7-7. MAT estimates ranged from ~13 to 17 °C (~55 to 63 °F) with an average of 14.4 °C. A rough estimate for precipitation for the upper horizon was produced using leaf area analysis (LAA, Table 7-8).

These estimates were obtained by using the largest Raunkiaer-Webb category represented by the morphotype (taken from the written description). This is similar to column “B” from the lower

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horizon (Table 7-4). The errors on the precipitation estimates should be considered minima because many of the leaves were fragmentary.

CLAMP and leaf mass per area (MA) analyses were not conducted for the upper horizon because the vast majority of the leaves were incomplete. The leaves were more fragmented than those of the lower horizon, indicating more significant transport from the source vegetation, which supports an allochthonous deposit.

Discussion of Paleoclimate Results

Leaf margin analysis estimated higher mean annual temperatures for the UF 19404 quarry as compared to the lower and upper horizons (comprised of multiple quarries). Based on the leaf physiognomic results, MAT declined through the >1 million years represented at Blue

Rim. This result agrees with decreasing regional temperatures after the peak warmth in the early

Eocene (Wing and Greenwood, 1993; Huber and Caballero, 2011). However, it is important to note that leaf physiognomic techniques tend to underestimate temperature because fossil leaves are derived from wet environments, which tend to have more toothed leaves. Kowalski and

Dilcher (2003) tried to account for this in their regression, which is why the temperature estimates using that equation are consistently higher (and more in line with other regional estimates). Furthermore, if any of the morphotype groupings are changed or more morphotypes are established in the future, the resulting paleoclimate estimates would also change.

The Blue Rim paleoclimate results will be compared to nearby fossil floras, including

Green River and Kisinger Lakes, in Part III of this chapter. However, the MAT estimates from the UF 19404 quarry and lower horizon (especially Kowalski and Dilcher’s equation) at Blue

Rim overlap with the estimates of 19 to 23 °C from the Kisinger Lakes flora in northwestern

Wyoming and the ~19 °C for the Green River flora, both of which relied on the taxonomic composition of the flora (MacGinitie, 1969; MacGinitie, 1974). 487

Past paleoclimate estimates from fossil floras have been used extensively by modelers for comparison (e.g., Sloan, 1994; Sewall and Sloan, 2006; Thrasher and Sloan, 2009, 2010).

Climate estimates from modeling in the early Eocene are in broad agreement with the estimates from the leaves at Blue Rim. Sloan (1994) recognized the importance of including the large interior lakes (e.g., those represented by the GRF) when modeling climate in the western interior.

Including the lakes and a CO2 level ~2 times that of present produced results that were similar to estimates given from the flora and fauna (Sloan, 1994). Including the lake in the model not only pushed the winter-freeze line northward, but also estimated a smaller area of freezing temperatures in the western USA (Sloan, 1994).

More recent regional modeling approaches, with smaller grid cells 50 by 50 km, also observed that increased CO2 levels and the inclusion of lakes produced climate estimates more in line with other climate proxies (Thrasher and Sloan, 2009, 2010). CO2 estimates for the early

Eocene (50-56 Ma) have ranged from 300 to 2700 ppm (Thrasher and Sloan, 2009). Beerling and

Royer (2011) compiled data from multiple proxies to reconstruct CO2 during the Cenozoic.

Although there were few data points for the early Eocene, CO2 ~49 Ma was estimated at just over 1000 ppm (Beerling and Royer, 2011). Thrasher and Sloan (2009) found that a CO2 level of

2240 ppm (as opposed to 560 ppm) produced temperature results more in agreement with other proxies. Temperatures in basins of western North America, including the Green River Basin, were estimated to be 10-16 °C; however, this figure is still lower than some estimates from leaf physiognomic approaches (Thrasher and Sloan, 2009).

Adding variation in land cover, including lakes and wetlands, to model temperature and precipitation during the early Eocene (50-56 Ma) also produced results similar to those of other proxy data. For example, in the grid cells that contained or surrounded a lake, MAT was ~3 °C

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higher and the range of MAT decreased up to 9 °C as opposed to areas where the land cover was defined as dry woodland (Thrasher and Sloan, 2010). Using this approach, climates estimates in the Green River Basin with a lake present were estimated as: MAT of 10-16 °C and CMMT 2-8

°C, both of which overlapped with other proxies including data from fossil plants (Thrasher and

Sloan, 2010). These numbers overlap with many of the estimates from Blue Rim; for example,

CLAMP estimated a CMMT of ~6-8 °C for the lower horizon at Blue Rim (Table 7-5). The modeled estimate for the range of mean annual temperature was higher than the proxies (20-22

°C vs. only ~16 °C from the lower horizon at Blue Rim), whereas the estimate for MAP was lower than the proxies (40-80 cm, Thrasher and Sloan, 2010) and estimates from Blue Rim

(~130-207 cm).

Sewald and Sloan (2006) modeled climate conditions in the western USA and found evidence for summer monsoons in the basins of the western USA including the Green River

Basin. The model estimated up to 1 cm of rain per day in the monsoon season which should be enough to support tropical vegetation (Sewall and Sloan, 2006). These high precipitation levels are also supported by the precipitation estimates from the lower horizon leaf flora at Blue Rim which estimated precipitation between 130 and 207 cm/year (LAA and CLAMP).

Part III: Comparison to Other Early Eocene Floras

Leopold and MacGinitie (1972) suggested the early to middle Eocene was subtropical based on their analysis of mostly pollen taxa. MacGinitie provided general temperature estimates to Roehler (1993) where he suggested the MAT of Wyoming ranged from 17-19 ºC during the early to middle Eocene. Floras from the early to early Middle Eocene of North America have yielded a range of temperature estimates depending on latitude and other factors. Multiple leaf margin analysis methods indicated a MAT range of ~35 ºC to 8 ºC over latitudes ~36-80 ºN,

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respectively (Fricke and Wing, 2004). Frost-intolerant plants such as palms, gingers, and cycads extended to high altitudes and latitudes (as well as lower latitudes) during the warm part of the

Eocene (Wing and Greenwood, 1993). Cold month mean temperatures ~45 to 55 Ma were estimated around 10 ºC from foliar physiognomic and NLR methods based on an examination of seven North American floras between ~39.2-48.5 °N (Wing and Greenwood, 1993).

Furthermore, Wilf (2000) estimated mean annual temperatures of 16-23 ºC from floras aged 53-

50 Ma in Wyoming using leaf margin analysis.

Kisinger Lakes. The ~48.5 Ma Kisinger Lakes flora, comprised of ~54 species including at least 40 angiosperms, is preserved in a floodplain deposit in the Aycross Formation in the

Wind River Basin of northwestern Wyoming (Berry, 1930; MacGinitie, 1974). The fern taxa at

Blue Rim, including Lygodium kaulfussi, Acrostichum sp., Asplenium sp., and Thelpteris iddingsi, are also present at Kisinger Lakes. Gymnosperm foliage is very rare at Kisinger Lakes and has not been recovered at Blue Rim; however both sites have multiple gymnosperm taxa in their dispersed palynoflora. Angiosperms represented by leaves that are shared between the Blue

Rim and Kisinger Lakes sites include: “Aleurites” fremontensis, Aristolochia sp., “Cedrela” schimperi, Cedrelospermum nervosum, Macginitiea sp., Platanus sp., “Serjania” rara,

“Symplocos” incondita, Syzygioides americana, and palm foliage. Salicaceae, including Populus sp. and Salix sp., are also present at both sites. Reproductive structures common to both sites include flowers of “Sunburst,” and “Mini Spike” and fruits/seeds of Chaneya tenuis, Iodes sp.,

Landeenia aralioides, Macginicarpa sp., Populus sp. and Vitaceae. However, numerous leaf types and reproductive structures are not shared between Blue Rim and Kisinger Lakes.

MacGinitie (1974) compared the Kisinger Lakes flora to various modern floras with a similar taxonomic composition to estimate a MAT of 19 to 23 °C with rare to no frost. MAP was

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estimated to be 89-140 cm with a winter dry season (MacGinitie, 1974). These temperature estimates overlap with those I obtained for Blue Rim using Kowalski and Dilcher’s (2003) LMA regression for both the UF 19404 site (20.37 ± 3.6 °C) and the lower horizon (18.56 ± 3.6 °C)

(Fig. 7-2). Kowalski and Dilcher’s (2003) equation was formulated to account for the fact that fossil leaves are most likely to be representative of the plants growing around or near a water body which tend to have a higher percentage of toothed leaves. Wolfe (1994) applied CLAMP to

MacGinitie’s (1974) Kisinger Lakes flora and estimated a MAT of 15.2 °C with a CMMT of ~5

°C; these temperatures are similar to or slightly cooler than the temperature estimates from Blue

Rim using leaf physiognomic approaches. Leaf area analysis (LAA) and CLAMP analyses from

Blue Rim estimated precipitation on the upper end of the range or slightly wetter than the

Kisinger Lakes site with the lowest MAP estimate from Blue Rim ~130 cm, ranging up to just over 200 cm per year.

Green River. The lacustrine Green River Formation, deposited from ~53.5 – 48.5 Ma

(Smith et al., 2003) in Wyoming, Colorado, and Utah, preserves an extensive fossil assemblage of plants, insects, and aquatic vertebrates. MacGinitie (1969) documented 77 plant species in the

Green River Formation (including specimens mainly from the Parachute Creek Member of Utah and Colorado and a few taxa from the Laney Member Little Mountain site in Wyoming); angiosperms were dominant (67 species) with a few pteridophytes and gymnosperms. Many of the same fern species are present in both the Green River and Blue Rim floras including

Acrostichum sp., Asplenium sp., and Lygodium kaulfussi. Occasional conifer foliage and seeds have been recovered in the Green River flora; gymnosperms are represented at Blue Rim by a single pinaceous wood specimen and dispersed pollen. Leaves of angiosperms present in both the

Green River and Blue Rim floras include: Populus cinnamomoides, likely Salix cockerelli,

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Cedrelospermum nervosum, Macginitiea wyomingensis, possibly “Aleurites” glandulosa, Rhus nigricans, Syzygioides americana, Platanus sp., and palm foliage. Fruits and flowers shared between the two sites include: Chaneya tenuis, Illigeria eocenia, Populus cinnamomoides,

Macginicarpa sp., Iodes sp., Pseudosalix-like flowers and “Mini Spike.” Flowers of Phoenix windmillis are also present in the Parachute Creek, Laney, and Fossil Butte Members of the

Green River Formation (Allen, 2015a). In contrast, the distinctive “Sunburst” flowers, which are common in the lower horizon at Blue Rim and occasionally preserved at Kisinger Lakes, have not been observed in the Green River flora. MacGinitie (1969) noted that the majority of the

Green River taxa including Platanus, Populus, legumes, and ferns were likely restricted to lake margin and floodplain areas. However, the Little Mountain locality had more basin margin and higher elevation taxa including Ephedra, Prunus, Pinus, and Fagus. More recently, the Little

Mountain flora has been interpreted as semi-deciduous with seasonally dry subtropical taxa

(Wing, 1987). Since the Blue Rim flora is preserved in what was the basin center, like most of the Green River flora, it is not surprising that most of the nearest living relatives of the fossil flora are found in low elevation, warm, moist sites.

The Fossil Butte Member (Fossil Lake, 53-51 Ma, Grande, 2013) of the Green River

Formation in southwestern Wyoming and northeastern Utah preserves a flora indicative of moist, subtropical conditions. Taxa shared with Blue Rim include: palms (e.g., Phoenix windmillis), ferns, Rhus, Equisetum, Platanaceae (leaves and fruits), rare Populus (leaves and fruits), legumes, Cedrelospermum nervosum, Chaneya tenuis, and Lagokarpos lacustris (Grande, 2013).

Conifers are rare in both the Fossil Lake and Blue Rim floras. Taxa recovered from the Fossil

Butte Member not yet observed at Blue Rim include: Typha, Nelumbo, Ceratophyllum,

Menispermaceae, and Platycarya (Grande, 2013).

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In estimating the paleoclimate of the Green River fossil flora, MacGinitie (1969) investigated the climate tolerances of the modern genera that the fossil taxa had been assigned.

Using these comparisons, MacGinitie (1969) estimated warm temperate to subtropical conditions with a MAT of ~19.4°C and a MAP of ~61-76 cm. Winters were likely dry with most of the rain falling in the warmer months. He (1969) also noted that although the climate may not have been frost free, temperatures likely did not fall much below freezing based on comparisons to the fossil’s nearest living relatives. Wolfe (1994) applied CLAMP to MacGinitie’s (1969) Green

River flora and estimated a MAT of 16.7 °C with a CMMT of ~9 °C. Wilf (2000) looked at the

Green River Little Mountain flora (upper Wilkins Peak Member and lower Laney Member) in southwestern Wyoming (~50 Ma) and found a frost-free, subtropical, warm climate. A MAT of

19.6 ± 2.1°C was estimated using leaf margin analysis and MAP of 75.8 cm was estimated using leaf area analysis (Wilf, 2000). Ferns and horsetails show that it was moist, while palms and gingers provide evidence of a frost-free climate (Wilf, 2000). The temperature estimates overlap with the highest LMA estimates from Blue Rim, especially for the UF 19404 site and the lower horizon. The precipitation estimates from the Green River flora are lower than the Blue Rim estimates.

Okanagan Highlands. The floras of the Okanagan Highlands including Republic

(Washington, USA), McAbee (British Columbia), and Falkland (British Colombia) are similar in age to Blue Rim. However, the floral composition and paleoclimate is quite different between southwestern Wyoming and the Okanagan Highlands region. Pinus, Metasequoia, Ginkgo,

Betula, Florissantia, Joffrea, and Ulmus are present at most Okanagan sites, with Betulaceae and

Sapindaceae the most speciose families (Dillhoff et al., 2005). These elements are rare, absent, or only present in the dispersed palynoflora at Blue Rim. Many of the Okanagan Highlands taxa,

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including species of Betulaceae, Hamamelidaceae, Trochodendraceae, and Rosaceae, are restricted to eastern North America or Asia today (DeVore et al., 2005). Others (e.g., Leopold and MacGinitie, 1972; MacGinitie, 1974) have also commented that the early Eocene floras from western North America have a lot of taxonomic overlap with the extant flora of southeast Asia.

In general, the Okanagan Highland sites are mild and equable with a MAT 10-15°C , CMMT

>0°C, and MAP >100 cm (Greenwood et al., 2005).

The lower Eocene lacustrine Republic (Washington, USA) site in the Klondike Mountain

Formation is ~49-50 Ma (Radtke et al., 2005; Mustoe, 2015). Republic is the most thoroughtly collected and apparently most diverse site of the Okanagan Highland floras with at least 68 vascular plant families represented (DeVore et al., 2005). Macginitiea is present at Republic, but it is not the same species as Blue Rim. Gymnosperm macrofossils including Metasequoia, Picea, and Ginkgo are also present at Republic (Wolfe and Wehr, 1987), whereas these are absent at

Blue Rim. Rosaceae is also well-represented at Republic along with other, frequently temperate families (e.g., Betulaceae, Ulmaceae, Wolfe and Wehr, 1987; Dillhoff et al., 2005; Pigg et al.,

2011). CLAMP has been used to estimate a MAT of 11.4 °C (Wolfe, 1994) and 10.0 °C (Wolfe et al., 1998) for the Republic site, whereas Greenwood et al. (2005) completed a bioclimatic analysis (similar to the Coexistence Approach) for the Republic flora and obtained an estimated

MAT of 13.5 ± 2.2 °C.

The early Eocene (52.9 ± 0.83 Ma, Gushulack et al., 2016) lacustrine flora preserved at the McAbee site near Cache Creek, British Columbia is dominated by Alnus, Betula, Ulmus, and

Fagus (Dillhoff et al., 2005; Manchester and Pigg, 2008). Gymnosperm macrofossils are common and diverse at McAbee (Dillhoff et al., 2005), unlike at Blue Rim. There is more taxonomic overlap between the McAbee and Blue Rim dispersed palynofloras than between the

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macrofloras. MAT has been estimated to be 9.5 °C using CLAMP and 13.5 ± 2.5 °C using NLR for the McAbee flora, whereas the CMMT was estimated to be -2 °C (CLAMP) to 3.5 ± 4.4 °C

(NLR, Dillhoff et al., 2005). More recent work confirmed these results with a MAT from leaf physiognomic approaches ranging between ~8-15 °C, CMMT ~5 °C, and WMMT ~21 °C

(Gushulack et al., 2016). These temperature estimates are much colder than those estimated from

Blue Rim (Fig. 7-2). These cool temperatures also help explain the lack of palm fossils recovered from McAbee (Dillhoff et al., 2005). The estimated MAP of 121 cm (CLAMP), ~100 to 130

(LAA and CLAMP) and 108 ± 35 cm (NLR) from McAbee (Dillhoff et al., 2005; Gushulack et al., 2016) are lower than all precipitation estimates from Blue Rim. Both the taxonomic composition and paleoclimate estimates from McAbee indicate a cooler, drier, and likely higher elevation site than Blue Rim in the early Eocene.

The Falkland flora, preserved in lacustrine facies in the Okanogan Highlands of British

Columbia, also has more gymnosperm macrofossil diversity and more temperate elements than

Blue Rim. Taxa that were found in all three units (only ~10,000 to 100,000 years apart) of the

Falkland site included: Metasequoia, Ginkgo, and Alnus (Smith et al., 2009a; Smith, 2011). None of these genera are present in the macroflora of Blue Rim. The taxa found at Falkland are similar to those of other sites in the Okanogan Highlands including Republic (WA, USA) and McAbee

(BC). In contrast to Blue Rim, the Falkland flora has considerably more gymnosperm taxa including conifers and Ginkgo with cuticle. Falkland and Blue Rim both have representatives of

Anacardiaceae, Ulmaceae, and Trochodendraceae, although not the same species (Smith et al.,

2009a; Smith, 2011).

Ferns and fern relatives are rare at Falkland and are limited to specimens of Adiantum,

Azolla, and Equisetum (Smith, 2011). Equisetum is present at Blue Rim, in addition to a few

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other fern taxa in the upper horizon, and Lygodium kaulfussi is abundant (especially in the lower horizon). However, monocot foliage is common at Falkland and relatively rare at Blue Rim.

Palm macrofossils have not been recovered at Falkland, another contrast to Blue Rim.

Conditions at Falkland were slightly cooler than palms can tolerate. The MAT at Falkland ranged from 8.9 ± 2.0 °C (LMA) to 11.9 ± 2.0 °C (CLAMP, Smith et al., 2009a; Smith, 2011).

This categorizes the climate as microthermal (MAT = <13 °C). The leaf area analysis estimated a

MAP of ~114 cm/year (Smith et al., 2009a; Smith, 2011).

California. The late Early Eocene Chalk Bluffs flora in California (~45 °N paleolatitude) had an estimated MAT of 16.5 °C with a CMMT of 7.1 °C, and a WMMT of 25.9 °C from

CLAMP (Wolfe, 1994). MacGinitie (1941) suggested this site received ~200 cm of summer rainfall. Based on these results, the warmest months were warmer and wetter than those at Blue

Rim.

The tidal lagoon Torrey Sandstone flora from Del Mar, CA is also estimated to be similar in age to Blue Rim at ~49-50 Ma (Myers, 1991). This flora is mostly composed of angiosperms plus Equisetum and Acrostichum. Angiosperm families represented in the Torrey Sandstone flora that are or likely present at Blue Rim include (macrofossils only): Lauraceae, Platanaceae,

Salicaceae, Caesalpinioideae (Fabaceae), Myrtaceae, Anacardiaceae (Myers, 1991). Myers

(1991) used NLR to estimate a frostless climate with a MAT of ~20 °C and a less than 8 °C range in mean temperature. MAP was estimated between 120 and 150 cm with most of the rain concentrated in the summer with drier winter months (Myers, 1991). It is important to note that the Torrey Sandstone flora is considerably further south than the other latest Early Eocene floras discussed here and it is preserved in a coastal rather than an inland site.

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Bighorn Basin (PETM). The Paleocene Eocene Thermal Maximum (~56 Ma) floras in the Bighorn Basin of north central Wyoming contain a mix of native species and plants that migrated in to the area during the warm episode (increase of ~5 °C, Wing and Harrington, 2001;

Wing et al., 2005). Significant shifts in plant range have been documented over a short period of time (~10,000 years) that overlaps with the thermal maximum (Wing et al., 2005; Wing and

Currano, 2013). For example, PETM sediments preserve fewer conifers and more legumes and palms than strata both before and after the peak warming event (Wing and Currano, 2013). Some taxa have only been recovered from PETM sites, whereas other taxa are only present before and/or after the PETM interval (Wing and Currano, 2013). Palynofloral elements include

Brosipollis, a taxon typically recognized from the early Eocene Gulf Coast region (Wing et al.,

2005). The most diverse groups in the PETM palynoflora, i.e., Juglandaceae, fern spores, and

Betulaceae/Myricaceae (Wing and Harrington, 2001), are also present in the Blue Rim dispersed palynoflora. Many plant taxa found in PETM specific strata are not found in other northern

Rocky Mountain floras or are only observed in more southern (e.g., Gulf Coast) floras (Wing et al., 2005). Wing and Currano (2013) comment that there is a significant amount of taxonomic overlap between the PETM floras and the Early Eocene Climatic Optimum (EECO, ~53-50 Ma) floras in the early Eocene. Populus cinnamomoides is present in PETM quarries, sites just after the PETM in the earliest Eocene (Wing and Currano, 2013), and at Blue Rim. Lygodium kaulfussi is present in the earliest Eocene of the Bighorn Basin (Wing and Currano, 2013) and is also very common at Blue Rim, especially in the lower horizon. Fruits of Landeenia aralioides have also been recovered from PETM floras from the Bighorn Basin (S. Wing and S.

Manchester, personal communication, Nov., 2016).

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MAT was estimated at 19.8 ± 3.1 °C (from LMA) during the PETM, which is higher than the estimated paleotemperature from plants from immediately before and after the PETM (Wing et al., 2005). This is warmer than the MAT estimates from Blue Rim with the exception of the oldest site, UF 19404 (Fig. 7-2). Leaf area analysis gave an estimated mean annual precipitation of 123 +177/- 86 cm for the PETM sites (Wing et al., 2005).

Insect herbivory was also higher during the PETM as compared to the surrounding intervals (Currano et al., 2008); insect herbivory levels are low at Blue Rim compared to other early Eocene sites including Falkland and Green River (Ellen Currano, personal communication,

July 2014; Wilf and Labandeira, 1999; Wilf et al., 2001; Smith, 2011). Insect herbivory is higher on deciduous taxa with short leaf life spans compared to evergreen taxa (Wilf et al., 2001). Less than half of the leaf morphotypes analyzed for MA from the lower horizon at Blue Rim suggested short, <1 year, life spans. Wilf et al. (2001) observed lower rates of herbivory after the EECO in seasonally dry climates. The Blue Rim floras were deposited after the EECO and had drier winters than summers with approximately half of the precipitation falling in the three wettest months. From the late Paleocene through the middle Eocene in the central Rocky Mountains, insect damage rates were highest on Macginitiea wyomingensis and Populus wilmattae (Wilf et al., 2001). Macginitiea wyomingensis is present in the UF 19404 quarry and the upper horizon and regularly has hole feeding. Populus wilmattae has not been observed at Blue Rim, but P. cinnamomoides is common, especially in the lower horizon, and occasional insect damage has been observed on the leaves of this taxon.

Part IV: Summary and Conclusions Based on this comprehensive survey of the paleobotanical elements preserved in the Blue

Rim escarpment, the area was well-vegetated with substantially sized trees, vines, lianas, and understory plants ~49 Ma. Warm temperate to subtropical taxa were able to flourish under warm,

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humid, wet conditions, with rare frost. The diffuse-porous woods preserved at Blue Rim also support a warm climate with low seasonality. The estimated vulnerability indices for the Blue

Rim woods were generally high (V >3), which is consistent with extant tropical woods. This suggests the tree taxa at Blue Rim did not experience significant water stress or regular freezing temperatures. Many extant Caesalpinioideae and Canellaceae species, both represented by wood taxa at Blue Rim, are found in tropical and subtropical environments today. The estimated climate conditions at Blue Rim are in agreement with estimates from early to middle Eocene floras from the Western Interior and from other proxies.

Our expanded understanding of the flora and paleoclimate of Blue Rim also helps to provide context for the well-known mammal fauna preserved in other sites of the early to middle

Eocene Bridger Formation. The fauna of Bridger 1b/A is dominated (number of specimens) by primates (including Notharctus robinsoni, Smilodectes mcgrewi, and Omomys carteri), rodents

(including Leptotomus sp. and Sciuravus nitidus), and perissodactyls (odd-toed ungulates, including Orohippus sp., Palaeosyops fontinalis, and Hyrachyus sp.; Gunnell, 1998). The primate taxa are omnivores or insectivores. Extant neotropical primates of intermediate size often consume a diet consisting mostly of fruit (Hawes and Peres, 2013). Fleshy fruits at Blue

Rim that might have been attractive to frugivorous primates include berries of cf. Ampelopsis rooseae (grape family) and drupes of Pentoperculum minimus (sumac family), and Iodes occidentalis. Members of extant Canellaceae (the family is only represented by wood at Blue

Rim) have red berries that may have been food sources for arboreal mammals. Date palms, represented by the flowers of Phoenix windmillis at Blue Rim, also produce sweet fruits. The rodent taxa were generally ground dwelling herbivores, whereas the perissodactyls were browsers. Leafy vegetation suitable for browsing would have been plentiful at Blue Rim ~49 Ma.

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The taxonomic composition and estimated paleoclimate of Blue Rim are similar to areas in southern China (e.g., Anshun, Guizhou Province) today. The climate of Anshun is slightly colder (CMMT ~2-4 °C too cold) and drier than the estimates from Blue Rim. Today, southern

China is classified as warm temperate with dry winters and hot summers (Cwa) according to the

Köppen-Geiger climate system (Kottek et al., 2006). Most of the extant genera (e.g., Iodes,

Lygodium, Populus, Rhus) represented in the Blue Rim flora have species in southeast Asia

(GBIF.org). The climate estimates from Blue Rim are also comparable to areas in Madagascar today. For example, the capital city of Antananarivo has a similar MAT and MAP to estimates from Blue Rim. However, Antananarivo has much more pronounced seasonality in its precipitation than estimates using CLAMP from Blue Rim. In general, Madagascar has a very diverse landscape and climate and is home to many primates, including all extant lemurs (Martin,

2003; Seiffert et al., 2003). The fossil primate taxa found in Br1b sediments, including species of

Notharctus, Smilodactes, and Omomys, had similar locomotion and were similar in size to extant lemurs and dwarf lemurs (Rose, 2006).

Forests (unlike woodlands or savannahs) require precipitation >1000-1100 mm (all MAP estimates from Blue Rim exceeded 1000 mm) per year (Jacobs, 2004; Jacobs and Herendeen,

2004). Forests typically have a minor dry season, whereas woodlands and savannahs have a pronounced dry season. Faunas that include a high proportion of arboreal frugivores and insectivores, like the Bridger fauna, also indicate warm conditions, a forested habitat, and year- round food resources (Wing and Greenwood 1993). The taxonomic composition of the plants, the presence of woody logs and stumps, the precipitation estimates, and the presence of arboreal mammals all suggest a forested, warm, and wet environment at Blue Rim in the latest Early

Eocene.

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This project has also produced a refined age estimate for the Blue Rim strata based on

40Ar/39Ar radiometric dating. The middle of the escarpment, just above the lower plant horizon at the base of the prominent blue marker bed, is 49.29 ± 0.18 Ma, whereas the very top of the horizon, above all plant horizons, is estimated to be 48.29 ± 0.45 Ma.

Work on the Blue Rim flora has contributed the recognition of new fossil taxa including

Phoenix windmillis (also present in the Green River Formation), Goweria bluerimensis, and

Iodes occidentalis (Allen, 2015a; Allen et al., 2015). Other new but yet to be identified taxa are also present including “Sunburst” (Homalieae, Salicaceae) and “Poofball” (Poales). Furthermore, the recognition of taxa at Blue Rim previously known from the regional flora expanded the range of those species. The families of Araceae, Arecaceae, Anacardiaceae, Canellaceae, Equisetaceae,

Fabaceae, Hernandiaceae, Icacinaceae, Meliaceae, Myrtaceae, Pinaceae, Platanaceae, Rutaceae,

Salicaceae, Sapindaceae, Schizaceae, Symplocaceae, Trochodendraceae, Ulmaceae, and

Vitaceae are each represented by at least one species in the Blue Rim macroflora. With the inclusion of the microflora, Amaranthaceae, Asteraceae, Betulaceae Cupressaceae, Ephedraceae, and Juglandaceae are also present. The combination of both the macrofossil and microfossil data from Blue Rim creates a floral gradient that spans from taxa that prefer warm, wet, likely low elevation conditions (most of the macrofossils) to taxa that were more likely to originate from higher elevation, drier, and cooler sites (many of the microfossils).

Challenges. Every project has its challenges and this was no exception. Sorting and morphotyping hundreds of leaf specimens at each stratigraphic horizon was one of the more difficult tasks. This is a partly subjective process and it is unlikely that another researcher would define the exact same leaf morphotypes if this were to be repeated in the future. Furthermore, additional fieldwork could yield new leaf types or better preserved specimens to clarify some of

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the current morphotypes that have few diagnosable characters or are only represented by one specimen.

Future work. There are two broad areas that I feel could use additional work on the Blue

Rim flora: 1) Exploring more taxonomic assignments for the unidentified leaf and reproductive macrofossils and 2) Expanding the study of the dispersed palynoflora. 1) Because I took a whole flora approach and wanted to document all organ remains preserved at Blue Rim, I did not have time to explore the taxonomic affinities of individual morphotypes as much as I would have if I had focused on fewer plant organs. Many of the leaf types have convergent morphology or are too poorly preserved to identify, but others have distinct characters that could help narrow down the taxonomic affinities with a more extensive search of extant genera. More work (e.g., comparing the fossil material to herbarium specimens) on the macro reproductive structures, might prove productive to identify some of the unusual, but currently unidentified remains. 2) A few more slides from Blue Rim with a well-preserved dispersed palynoflora still need to be documented and studied. The taxonomic affinities of the distinctive, but unidentified grains could be explored further. However, pollen and spore morphology can be convergent among groups and the taxonomic resolution is often lower than well-preserved macrofossils. In addition, a known quantity of Lycopodium spores was added to each slide to aid in future questions necessitating counting the number of palynomorphs per volume of sediment. This palynoflora, like that from Kisinger Lakes, has been documented mainly by transmitted light microscopy. It would be desirable to supplement this work with scanning electron microscopy of the same grains to recover fine details of ornamentation (as was done in recent work on the palynoflora of

Florissant, Bouchal et al., 2016).

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Final remarks. The Blue Rim flora highlights the breadth of information that can be gleaned from floras that preserve multiple organs. We now have a better understanding of the taxonomic composition, overall diversity, forest structure, and paleoclimate of the Bridger

Formation as represented at this previously poorly documented latest Early Eocene site in southwestern Wyoming.

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Table 7-1. Mean annual temperature (MAT) estimates using leaf margin analysis (LMA) for the UF 19404 site at Blue Rim. MAT Formula Geographic range of modern Reference estimate floras used to create regression (°C) a MAT = [(30.6*P) East Asia Wolfe, 1979; Wing and 16.44 ± 0.8 + 1.14] Greenwood, 1993 a MAT = [(28.6*P) North, Central, and South Wilf, 1997 16.54 ± 2 + 2.24] America a MAT = Southeast USA Kowalski and Dilcher, 20.37 ± 3.6 [(0.363*P) + 2003 2.223] b MAT = North and Central America Miller et al., 2006 15.82 ± 6.5 [(28.99*P) + 1.32] a MAT = 92 globally dispersed sites Peppe et al., 2011 14.80 ± 4.8 [(0.204*P) + 4.6] P = percent untoothed a = Standard Error; b = 95% Confidence Interval; estimated from Fig. 2B in Miller et al., 2006 (based on the number of taxa in the sample)

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Table 7-2. Mean annual precipitation (MAP) estimates using leaf area analysis (LAA) for the UF 19404 site at Blue Rim. MAP Formula** Geographic range of modern Reference estimate floras used to create regression (cm)$* 159.36 ln(MAP) = Tropical and subtropical new Wilf et al., 1998 +69.1, -48.2 0.548 (MlnA) + world, plus 7 sites in Africa and 3 0.768 sites in temperate North America 145.48 ln(MAP) = 12 sites from low to high Gregory- +35.8, -28.7 0.298 (MlnA) + elevation in Bolivia Wodzicki, 2000 2.64 159.77 ln(MAP) = Wilf et al., 1998 and Gregory- Jacobs, 2002 +64.7, -46.0 0.429 (MlnA) + Wodzicki, 2000 datasets plus 1.705 tropical Africa 171.10 ln(MAP) = 92 globally dispersed sites Peppe et al., 2011 +143.8, -78.1 0.283 (MlnA) + 2.92 $Largest Raunkiaer-Webb category represented by the morphotype (taken from the written description). Similar to column “B” from the lower horizon. MlnA = ∑aipi (ai is the mean of the natural log of the seven Raunkiaer-Webb size categories while pi is the proportion of morphotypes in each category). *The standard error is asymmetrical because it was converted from logarithmic units. **MlnA method is based on the work of Givnish (1984).

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Table 7-3. Mean annual temperature (MAT) estimates using leaf margin analysis for the lower horizon quarries at Blue Rim. MAT Formula Geographic range of modern Reference estimate floras used to create regression (°C) a MAT = [(30.6*P) East Asia Wolfe, 1979; Wing and 14.91 ± 0.8 + 1.14] Greenwood, 1993 a MAT = [(28.6*P) North, Central, and South Wilf, 1997 15.11 ± 2 + 2.24] America a MAT = Southeast USA Kowalski and Dilcher, 18.56 ± 3.6 [(0.363*P) + 2003 2.223] b MAT = North and Central America Miller et al., 2006 14.37 ± 7 [(28.99*P) + 1.32] a MAT = 92 globally dispersed sites Peppe et al., 2011 13.78 ± 4.8 [(0.204*P) + 4.6] P = percent untoothed a = Standard Error; b = 95% Confidence Interval; estimated from Fig. 2B in Miller et al., 2006 (based on the number of taxa in the sample)

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Table 7-4. Mean annual precipitation (MAP) estimates using leaf area analysis (LAA) for the lower horizon quarries at Blue Rim. A: MAP B: MAP Formula** Geographic range of modern Reference estimate estimate floras used to create regression (cm)* (cm)* 129.94 192.68 ln(MAP) = Tropical and subtropical new Wilf et al., +56.3, -39.3 +83.5, -58.3 0.548 (MlnA) + world, plus 7 sites in Africa 1998 0.768 and 3 sites in temperate North America 130.20 161.31 Ln(MAP) = 12 sites from low to high Gregory- +32.0, -25.7 +40.0, -31.9 0.298 (MlnA) + elevation in Bolivia Wodzicki, 2.64 2000 136.17 185.37 ln(MAP) = Wilf et al., 1998 and Gregory- Jacobs, +55.1, -39.2 +75.1, -53.4 0.429 (MlnA) + Wodzicki, 2000 datasets plus 2002 1.705 tropical Africa 153.98 188.73 ln(MAP) = 92 globally dispersed sites Peppe et +129.4, -70.3 +158.6, -86.2 0.283 (MlnA) + al., 2011 2.92 A: Raunkiaer-Webb category using mean of area of smallest and largest leaf. Area = 2/3length x width. B: Largest Raunkiaer-Webb category represented by the morphotype (from the measured largest leaf; area = 2/3length x width). MlnA = ∑aipi (ai is the mean of the natural log of the seven Raunkiaer-Webb size categories while pi is the proportion of morphotypes in each category). *The standard error is asymmetrical because it was converted from logarithmic units. **MlnA method is based on the work of Givnish (1984).

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Table 7-5. CLAMP results from the 20 morphotypes from the lower horizon at Blue Rim. Nearby meteorological Global gridded model CLAMP parameter* stations (Met3brc)**+^$ (GRIDMET3brc) +^$ MAT °C 15.34 ± 2.0 14.07 ± 2.1 WMMT °C 23.63 ± 2.7 22.23 ± 2.5 CMMT °C 7.93 ± 3.4 6.27 ± 3.4

GROWSEAS 8.74 ± 1.1 8.00 ± 1.1

GSP cm 207.01 ± 48.3 165.32 ± 31.7

MMGSP cm 23.60 ± 5.2 19.89 ± 3.8

3-WET cm 95.95 ± 20.6 86.03 ± 22.9

3-DRY cm 49.60 ± 13.7 23.50 ± 5.9

RH % 76.27 ± 11.1 78.09 ± 8.6

SH 9.55 ± 1.7 9.45 ± 1.7

ENTHAL 31.33 ± 0.6 32.41 ± 0.8 * Acronym definitions as following: MAT = mean annual temperature; WMMT = warm-month mean temperature; CMMT = cold-month mean temperature; GROWSEAS = growing season length in months; GSP = mean growing season precipitation (similar to MAP); MMGSP = mean monthly growing season precipitation; 3-WET = three consecutive wettest months; 3-DRY = three consecutive driest months; RH = relative humidity; SH = specific humidity; ENTHAL = enthalpy **Nearby meteorological stations use 30 years of climate data. + The 3brc datasets have 144 modern floras. ^The error is representative of the standard deviation calculated for each of the 11 climate variables. The modern vegetation samples were each removed from the dataset and treated as passive (so they more closely reflect a fossil sample) and the observed and predicted values were compared. $Met3brc and GRIDMET3brc indicate which meteorological data was used. Met3brc uses the more traditional CLAMP approach where data from climate stations near each modern vegetation site is recorded. GRIDMET3brc is a newer method where the climate data is obtained from globally gridded meteorological data (New et al., 1999) which has been adjusted for elevation (Spicer et al., 2009). The global gridded climate data estimates are better for comparison to modern regional estimates often used in climate modeling (see http://clamp.ibcas.ac.cn/ for more information).

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Table 7-6. Leaf Mass per Area (MA) results for leaves from the lower horizon at Blue Rim. 2 Morphotype # specimens Average MA (g/m ) Time represented (in years) SR 10 107.6 ~1 HT 2 75.9 <1 ATR 1 107.9 ~1 TDA/PS 3 105.2 ~1 PC 6 97.7 ~1 BTOS 1 99.1 ~1 TT 1 70.2 <1 CBT 3 71.8 <1 AF 2 75.5 <1 BTBP 2 72.8 <1 GB 11 109.1 ~1 TCE 3 83 <1 VCT 11 92.1 ~1 TRB 3 127.1 ~1 All specimens 59 92.5 ~1 2 2 MA values <87 g/m were interpreted to have leaf lifespans <1 year, values >129 g/m were interpreted to have leaf lifespans >1 year, and intermediate values indicated a leaf lifespan of ~1 year (per Royer et al., 2007).

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Table 7-7. Mean annual temperature (MAT) estimates using leaf margin analysis (LMA) for the upper horizon at Blue Rim. MAT Formula Geographic range of modern Reference estimate floras used to create regression (°C) a MAT = [(30.6*P) East Asia Wolfe, 1979; Wing and 13.89 ± 0.8 + 1.14] Greenwood, 1993 a MAT = [(28.6*P) North, Central, and South Wilf, 1997 14.16 ± 2 + 2.24] America a MAT = Southeast USA Kowalski and Dilcher, 17.35 ± 3.6 [(0.363*P) + 2003 2.223] b MAT = North and Central America Miller et al., 2006 13.40 ± 6 [(28.99*P) + 1.32] a MAT = 92 globally dispersed sites Peppe et al., 2011 13.10 ± 4.8 [(0.204*P) + 4.6] P = percent untoothed a = Standard Error; b = 95% Confidence Interval; estimated from Fig. 2B in Miller et al., 2006 (based on the number of taxa in the sample)

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Table 7-8. Mean annual precipitation (MAP) estimates using leaf area analysis (LAA) for the upper horizon quarries at Blue Rim. MAP Formula** Geographic range of modern floras Reference estimate used to create regression (cm)$* 151.69 ln(MAP) = Tropical and subtropical new world, Wilf et al., 1998 +65.7, -45.9 0.548 (MlnA) plus 7 sites in Africa and 3 sites in + 0.768 temperate North America 141.63 Ln(MAP) = 12 sites from low to high elevation in Gregory- +34.9, -28.0 0.298 (MlnA) Bolivia Wodzicki, 2000 + 2.64 153.72 ln(MAP) = Wilf et al., 1998 and Gregory- Jacobs, 2002 +62.2, -44.3 0.429 (MlnA) Wodzicki, 2000 datasets plus tropical + 1.705 Africa 166.80 ln(MAP) = 92 globally dispersed sites Peppe et al., +140.2, -76.2 0.283 (MlnA) 2011 + 2.92 $Largest Raunkiaer-Webb category represented by the morphotype (taken from the written description). Similar to column “B” from the lower horizon. MlnA = ∑aipi (ai is the mean of the natural log of the seven Raunkiaer-Webb size categories while pi is the proportion of morphotypes in each category). *The standard error is asymmetrical because it was converted from logarithmic units. **MlnA method is based on the work of Givnish (1984).

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0.5

0.4

0.3

0.2

0.1 Proportion speciesof

Leaf mass per area (g/m²)

Figure 7-1. Leaf mass per area summary from the lower horizon at Blue Rim. Fourteen of the twenty morphotypes had at least one specimen with both area and petiole width. Bin categories are the same as Figure 3 in Royer et al. (2010) for comparison.

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Figure 7-2. Estimated paleotemperatures from nine early Eocene and PETM localities including Blue Rim (BR). Estimates using different methods (NLR, CLAMP, LMA) for the same flora are indicated. The Republic, McAbee, and Falkland floras of the Okanagan Highlands (British Columbia) are the coolest. Paleotemperature results from Blue Rim are similar to those from the other early Eocene sites and the PETM flora from the Bighorn Basin in northcentral Wyoming. The LMA results from Blue Rim represent the average of the five different regressions used, whereas the warmest estimates are from Kowalski and Dilcher (2003) and the coldest are from Peppe et al. (2011). Sources cited in the text. Figure created by Jared Desrochers.

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APPENDIX A SUPPLEMENTAL DATA FOR CHAPTER 1

Table A-1. Notes from the 2012 stratigraphic section including plant locality UF 19225. Unit Thickness Description 1 17’5’’ Moderately well-sorted friable sandstone. Very fine to fine grain size; 5.31 m color is grey; beds are poorly defined but appear horizontal. Interbedded with finer grained well-sorted friable siltstone. Color is grey with some gypsum crystals, and minor iron staining. Siltstone is slightly blocky, breaks into rounded chunks. Sandstone is a bit more layered than siltstone. Unit does not fizz with HCl and lacks cross beds and ostracods.

2 4’6’’ Thinly laminated siltstone/sandstone that is more friable than Unit 1. 1.37 m Very fine well-sorted sand. Unit does not fizz with HCl and lacks cross beds and ostracods.

3 21’’ Unconsolidated, well-sorted, olive green fine sand. Possible paleosol? 0.53 m Unit does not fizz with HCl and lacks cross beds and ostracods.

4 3’ Thinly laminated (~1 mm) well-sorted siltstone. Color is whitish to olive .91 m grey. Interbedded with poorly developed paleosols? Paleosols? are yellowish brown, well-sorted unconsolidated fine sand, and blocky. Unit fizzes with HCl, but lacks cross beds and ostracods.

5 7’3’’ Unit 5 is composed of reddish brown weathering sandstone that forms 2.21 m small ledges and caps the first flat area of this badland finger. The fresh color is reddish grey. Lithology is mixed with quartz, feldspar (orthoclase = reddish?), and hornblende? (black specs). Unit varies from moderately to poorly sorted with a variable grain size. Grain size is mostly medium sand with rare grains up to very coarse sand. It is almost a small conglomerate in a reddish matrix. Quartz and other clasts are subangular. The weathering makes it difficult to determine if the unit fines upward or not. Also, there is modern soil on the surface with living vegetation; this is a relatively flat area. Unit fizzes with HCl, has poorly to moderately developed cross beds in some areas, and lacks ostracods.

6 5’6’’ This unit forms a gradual slope that weathers easily. The weathered 1.68 m surface is whitish grey with iron staining. Fresh surfaces are grey. The matrix is generally homogenous and well-sorted silt to very fine sand. The unit breaks easily and is composed of uneven thin (3-10 mm) layers with iron staining. Unit does not fizz with HCl and lacks cross beds and ostracods.

7 7’5’’ Well-sorted greenish grey fine to very fine sandstone. Sandstone is 2.26 m composed of quartz, feldspar, and specs of a black mineral (biotite). Unit 7 breaks easily, but is a bit more resistant than the previous unit. Some

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areas are blocky, whereas others have 0.1-2 cm layers. There are sporadic units of reddish sandstone at the base of Unit 7 that may represent small channels. Poorly developed cross beds present in reddish sandstones. Main unit does not fizz with HCl, but reddish sandstones/limestones do. Ostracods are absent.

8 5’ Unit 8 weathers to a steeper, more vertical slope than the previous unit. 1.52 m Surface color is light olive brown grey. Resistant sandstone 1-2 feet wide by 3 inches thick protrude from the unit. Above this, a large chunk of petrified wood (looks like a former Aom site) present. A lot of the wood pieces are weathering down the hill. The protruding sandstone units are similar to the ones described previously – weather brownish red, whereas the fresh surface is bluish grey. Lithology of the sandstone includes quartz, feldspar, and hornblende/muscovite. Sandstone units are mostly massive, but have undeveloped laminations, that may or may not be due to weathering. The upper part of the unit is more coarse-grained and poorly sorted. Larger grains are medium to coarse sand in size and subangular. Matrix is very fine sand. The lithology of the grains is variable, the majority being quartz and feldspar. Poorly developed cross beds in some areas of the reddish sandstones. Main unit does not fizz with HCl, but reddish sandstones/limestones do. Ostracods are absent.

9 7’10’’ Unit is whitish grey that weathers to light yellowish grey. Unit is blocky 2.39 m with some gypsum. Lithology is homogenous with well-sorted very fine sand to silt. No obvious sedimentary structures, including cross beds, are preserved. There is some petrified wood. Higher up in the section preserves finer wavy laminations (sub cm scale). Sediment is slightly coarser with fine to very fine sand. Overall the unit is compatible throughout – there is just more weathering near the top. Iron staining is present on the surface. Unit does not fizz with HCl and lacks ostracods.

10 10’ Beds are nearly horizontal with a variable lithology. Gypsum crystals are 3.05 m present. The overall section weathers a yellowish bright grey with lots of iron staining on the surface, especially in the lower section. The lower and upper sections are more sandy, while the center of the unit is more fine grained like some of the previous units. The lower level is subrounded, well-sorted, fine to medium sand and light to medium grey in color where it is not stained. The center of the unit (a bit past halfway up) is more olive grey and finer grained. Sediment is well-sorted and very fine sand in grain size. The top of the unit is well-sorted and yellowish dark grey in color. Lithology is mixed with quartz, feldspar, and black- colored minerals present. Unit does not fizz with HCl and lacks cross beds and ostracods.

11 10’ Unit is sandstone that weathers brownish red. Grains are sub-angular to 3.05 m sub-rounded (hard to see). Unit is silica rich with mostly quartz and

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feldspar and a few shiny black flecks. Fresh surfaces are bright grey and well-sorted. There are some lenses weathering out that preserve lamina that are less than 5 mm thick. Poorly to moderately developed cross beds in some areas of the reddish sandstones. Grain size of this unit is fine sand. Unit fizzes with HCl and lacks ostracods.

12 15’ This is the leaf layer (UF 19225); it is full of organics, matted leaves, and 4.57 m plant fragments. The leaf mats and plant fragment hash are preserved in the lower part of the unit in very flaky layers (some <1mm thick) of coarser grained material. The coarser grains are predominately silt with some very fine sand. The finer material is clay/mudstone. The color of this unit varies from brownish grey to yellowish grey with some areas of iron staining. This unit forms a plateau in the section and has some modern soil and vegetation on top. Gastropods are occasionally preserved. There is a thin carbonaceous layer near the base. Unit does not fizz with HCl and lacks cross beds and ostracods.

13 15’ Well-sorted greenish grey sandstone. Unit has a homogenous texture and 4.57 m is composed of very fine sand. The overall unit is variable: somewhat blocky near the base, whereas the middle has more defined layers that split easily into sheets 1-5 mm thick; the unit is capped by a flat surface composed of friable paper shales with iron staining (likely the base of the blue layer/unit 14). Overall, the unit fines upward. Unit also contains thinly bedded sandstones that weather out in fragmented brownish red pieces. Surface of unit is bleached and fragments of turtle shell and agate/chalcedony were weathering out on the surface. Unit fizzes with HCl, especially in the ledge at the base of the blue layer that is likely limestone; base of unit does not fizz as vigorously. Cross beds and ostracods are absent.

14 32’ 2” This is the classic “blue” layer for which Blue Rim gets its name. The 9.80 m weathered surface is greyish blue while the fresh material is chlorite to light malachite green. Unit is blocky; a few of the blocks are laminated and relatively flat on the top and bottom while others are either botryoidal or angular. The composition is homogenous well-sorted very fine sand. There are occasional patches of broken, brownish red sandstone weathering out. Main unit does not fizz with HCl, but reddish sandstones/limestones do. Cross beds and ostracods are not present.

15 17’ 8.5” Weathered surface is composed of stripes of whitish tan and brownish 5.40 m red colored sediment. Petrified wood fragments are present on the surface. This unit is resistant and blocky (large angular blocks) and the transition from the previous unit is unclear, which makes the exact boundary hard to determine. Sediment is very fine sand in size and the fresh material is greenish grey in color. The more friable pieces are slightly coarser (fine sand) and have a more variable lithology. Grains

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are sub-angular. The top of the unit preserves a thin discontinuous bed of brownish red sandstone. This preserves evidence of turtle shells, mollusks, and gastropods. Fresh surfaces of the sandstone are greenish grey. Some of the mollusks have mother of pearl preserved. A weathered vertebrate bone fragment 0.5-1 cm was found on the surface. Overall, the bottom of the unit is more resistant, blocky and finer grained than the coarser middle. The top of the unit preserves the discontinuous red sandstone ledge. Poorly developed cross beds are visible in the reddish sandstones near the top of the unit. The bottom and top 1/3 of the unit fizz with HCl, but the middle section does not. Ostracods are not present.

16 4’ 6” This thin unit weathers as an off white band between two more reddish 1.37 m bands. The fresh surface is greenish grey. Homogenous, well-sorted material is silt in size and unit varies from blocky and angular to more rounded pieces. Unit does not fizz with HCl and lacks cross beds and ostracods. (*This unit has similarities to the upper blue band in the UF 19297 section).

17 5’ The weathered surface of this (not very resistant to erosion) unit is 1.52 m reddish tan, while the fresh rock is bluish grey. The lithology is mixed and includes quartz, feldspar, and dark minerals. Grain size is fine sand; grains are subangular to subrounded. There is some brownish red sandstone/conglomerate weathering out of the unit. The clasts are 1 mm to 1 cm in diameter and the unit is poorly sorted. The grains are subangular to subrounded. Overall, this is a rather confusing layer. Unit fizzes with HCl, but lacks cross beds and ostracods.

18 5’ 10” This unit is sulfur and iron rich with lots of staining. It contained pieces 1.78 m of fossil wood and plant hash that was mostly monocots. The fresh rock is bright off-white. The grains are all similar in color and ranged up to medium sand in size. The plant fragment layer is thin and in the middle of the unit. Darker rock is preserved above the plant layer that is yellowish grey in color with lots of reddish brown staining. Petrified wood was also found on the surface. Some carbonaceous material was also present. Unit does not fizz with HCl and lacks cross beds and ostracods.

19 20’ 5” This unit was quite unconsolidated and preserved thin lamina of 6.22 m compacted sand. Whereas the weathered surface was whitish tan, the fresh surface was yellowish brown in color. Grains were sub-rounded and fine sand in size. The unit was slightly variable as a bit higher up it was brownish grey and had a mixed lithology that included more light (colored) minerals. The grain size in the upper section was very fine sand. Even higher up section, the unit was more resistant to erosion. Near the top, the color was light olive grey and the sediment was silt to very fine sand in size. The unit fined upward a bit with brownish red

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sandstone weathering out near the top. This was composed of a red matrix with white to clear clasts that were very fine sand in size. The main unit does not fizz with HCl, but the reddish sandstones/limestones do. Cross beds and ostracods are absent.

20 8’11” The surface color is variable from light grey to brown. Matrix is sandy 2.72 m with sulfur and iron, often in nodules. Some gypsum is present. Fresh surfaces are yellowish grey/brown. Lithology is mixed; grains are subangular and vary from fine to medium sand in size. Unit is moderately well-sorted with a bit of brownish red sandstone weathering out. This sandstone/limestone looks the same as the previous unit. Unit does not fizz with HCl and lacks cross beds and ostracods.

21 19’4” This is a variable unit and it was unclear whether to split it further or not. 5.89 m The weathered surface is greenish bright grey to light brown. The variable rock is a greenish bright grey matrix with larger white grains. Matrix is very fine sand in size with some silt. Layers are inter-bedded, some do not have the larger white grains. Unit also contains layers/patches of friable siltstone; these do not have larger clasts. Gypsum is also present in the middle of the unit. The top and bottom of the unit are sandier. Iron staining is present near the top of the unit. The main unit does not fizz with HCl, but the reddish sandstones/limestones do. Cross beds and ostracods are absent.

22* 14” This is the first of two resistant capping ledges. The thinly bedded 0.36 m shale/siltstone formed 1-2 mm thick layers. This homogenous unit weathers from red to bluish grey to yellowish tan. Fresh unweathered surface is more tan in color. Unit fizzes with HCl, cross beds are absent, but ostrocods are present.

23* 5’ This more erosive layer is in between the two capping units. It is 1.52 m bleached white with iron stained layers. Fresh surface is yellowish grey. Unit is homogenous with silt and clay sized grains. Much of the unit is composed of eroded sediment. In general, the unit does not fizz with HCl, but occasionally reacted, likely due to pieces weathering down the slope from above. There was no clear place to observe cross beds or ostracods.

24* 8” This is the main capping sandstone/limestone unit. Weathered color 0.20 m varies from brownish red to orangey tan to bluish grey. It is composed of homogenous very fine sand/silt. Rare Goniobasis are preserved. Grain size is coarser than unit 22. Unit fizzes with HCl, but cross beds and ostracods are absent.

25 18’8” This upper thin blue layer is intermittent and not always present across 5.69 m the badlands escarpment. Fresh surface is dark greenish grey, whereas

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the weathered color is greenish grey to tan. This friable unit is homogenous, well-sorted very fine sand to silt. Unit forms a shallow slope. It is unclear where the true Eocene material transitions to younger, more recent material, so the top of the unit was estimated. Unit fizzes slightly with HCl, but may be contaminated; cross beds and ostracods absent.

26 6’ This uppermost unit follows the surface topography and contains recent 1.83 m sediment with wind varnished pebbles and living vegetation. Poorly sorted, very fine sand and larger. Desert varnish/Wind River Formation pebbles are up to cobble in size. Unit only fizzes with HCl where contaminated with limestone/marlstone. Cross beds and ostracods absent. Thickness of unit slightly variable between 5-7’.

Total 255’ 5” 77.74 m Note. Stratigraphically, unit 1 is the oldest at the bottom of the escarpment; unit 26 is the youngest at the top of the section. Colors are representative of my observations and do not correspond to a specific color chart (e.g., Munsell). *Units 22-24 were lumped together in the stratigraphic section after further review.

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Table A-2. Notes from the 2014 stratigraphic section including plant locality UF 19297. Unit Thickness Description 1 38’ 2’’ Unit is yellowish gray in color, unconsolidated fine sand, subrounded 11.63 m grains, with scattered sagebrush vegetation on surface. From 25 to 27 feet there are scattered intermittent reddish sandstones similar to the ones in the 19225 strat section; weathered surfaces of these are reddish brown, fresh surface is gray. Angular crystals are clearly visible with a hand lens, mostly light colored minerals—quartz and feldspar with a few darker specs, maybe biotite. Grain size in these intermittent channel type sandstones is medium sand. Unit is capped by a thinly laminated reddish brown to bluish gray siltstone. There is plant hash in this layer above the reddish brown sandstone and before the large bench. The protruding sandstones ~3/4 the way up the unit have no evidence of ostracods. They have poorly to moderately developed cross beds. There are plant hash layers above this; they are laminated, laminations are 3-5 mm, grain size silt. These layers do not fizz, however the unit overall has a strong reaction to HCl. Capping unit laminations are 2-15 mm thick, most in the range of 3-4 mm. Capping unit does have ostracods.

2 5’ The top of this unit creates a broad nearly flat shelf on this badland finger 1.57 m and the neighboring ones. Sediment is light, yellowish gray and surface is vegetated. Fresh sediment is brownish gray. Grains are subrounded and fine to very fine sand. It is too unconsolidated to see cross beds, but ostracods are present. Unit fizzes strongly upon contacting HCl.

3 26’ This is the thick blue layer. The lower part has thin laminations (~1 mm 7.92 m thick). Color is greenish gray. Grain size is silt with a homogenous mineralogy. Just above this are occasional patches of 2-3 mm thick with a mix of clast sizes from coarse to fine sand. Above this is a blocky subunit; surface color is greenish gray while the fresh color is a light malachite green. Texture and mineralogy is homogenous with very fine sand to silt grain size. Unit is capped by a thin (1-3 mm) layers that are light malachite green. Grain size is silt with homogenous mineralogy. In some areas there are thin light brown layers in the upper part of the thicker lower blue layer. This unit has pumice, biotite and is representative of a tuff. Some areas of the unit react with HCl, whereas others do not. No visible ostracods or cross beds present.

4 15’ 10’’ Surface color is light brown, fresh color is slightly darker. Bone and 4.83 m turtle shell fragments are preserved on the surface. This unit weathers steeply, is less resistant, and the near surface material is unconsolidated. Grain size is fine sand. There are lots of quartz and feldspar grains visible. Grains are subrounded.

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No obvious ostracods or cross beds present, hard to get a fresh surface though. Unit does not fizz when exposed to HCl.

5 8’ 4’’ The upper blue layer is split unto three smaller layers by yellowish to 2.54 m brownish layers. This lowermost unit of the upper blue layer is light greenish gray on fresh and weathered surfaces. Near the surface, unit is laminated; laminations are 1-3 mm thick. Underneath, texture is blocky. Grain size is silt to very fine sand. Mineralogy is homogenous. Bit of pumice observed; no obvious cross beds or ostracods present. Unit does not fizz with HCl.

6 6’’ This is a thin layer between the blue layers. This unit is capped by a 0.15 m resistant calcareous sandstone. Clasts are rounded and up to medium sand in size. Matrix is silt to very fine sand. Weathered color is brownish red, whereas the fresh color is yellowish gray. Unit is slightly laminated. Thickness is variable, some blocks are many cm thick. Numerous ostracods present, no obvious cross beds. Unit fizzes strongly with HCl.

7 41’’ Middle blue layer of upper blue band. Surface color is light bluish green, 1.04 m while the fresh color is light malachite green. Unit is flaky near the surface and blocky underneath. Grain size is silt to very fine sand. Other characters are similar to previous blue unit. No obvious ostracods or cross beds visible. Unit fizzes strongly with HCl.

8 43” This is the upper dissecting tan layer of the upper blue. It is filled with 1.09 m spiral gastropods (Goniobasis / Elimia). Weathered surface is brownish red, whereas the fresh surface is greenish gray. The gastropods are numerous. Grain size is fine sand; grains are subrounded. Quartz and feldspar are visible. Laminations are poorly defined and layers can be multiple cm thick. Possible poorly defined cross beds; occasional ostracods? It is hard to tell whether they are ostracods or coarse clasts, but most look like sand. Unit fizzes strongly with HCl.

9 32” This is the final blue layer of the upper blue unit. There are large reddish 0.81 m brown concretions that fizz with exposure to HCl, even though the blue material does not. Bone, turtle shell, and gar fish scales were found on the surface; these likely eroded down from the units above. Grain size is silt to very fine sand. Other characters are the same as previous blue layers. No obvious cross beds or ostracods present. There are white bits that are likely pumice.

10 18’ 5’’ Weathered surface color is medium tan; fresh material is light greenish

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5.61 m gray. Unit is thinly laminated near the surface, but quickly transitions to blocky. Grain size is silt with a homogenous texture and mineralogy. There are scattered chunks of petrified wood on the surface that likely eroded down from the unit above this one. No obvious ostracods or cross beds present. There are white bits, possibly pumice. Unit does not react to HCl.

11 54’’ Petrified wood is present as is sulfur and iron staining. I could see 1.37 m something similar on other nearby badland fingers – this is the only place on this slope with scrubby sagebrush – the topography is slightly flatter. Surface color is yellowish gray. Fresh material just under surface is off- white, well-sorted, very fine sand. Solid chunks a bit deeper are light yellowish gray with iron and sulfur staining. It looks like it would have plant hash/fragments, but none were observed. Grain size is silt; light colored minerals are present. Possible paleosol? Or a little lens? No obvious cross beds or ostracods present. There are some long, skinny quartz or orthoclase orange-colored crystals. Neither these nor the unit matrix fizz with exposure to HCl. (This unit looked slightly tuffaceous to me, but M.E. Smith walked right it). There are scattered thin patches (~2 mm thick) of coal and bits of pumice too.

12 20’ 5’’ Surface color is light brown; fresh sediment is yellowish light brown. 6.22 m This unit weathers pretty steeply. Grains are subangular, well-sorted, fine to medium sand. Grains are mostly quartz and feldspar with some dark minerals. About halfway up the unit is slightly coarser (medium sand) with visible pieces of biotite in the matrix. The underlying rock is medium sand with biotite, but the surface material is the finer grained material described first. No obvious cross beds or ostracods. Unit does not react to HCl.

13 15’ 9’’ Surface color is light brownish tan transitioning to light yellowish tan. 4.80 m Fresh material is yellowish gray well-sorted, homogenous very fine sand to silt. Fresh material closer to the top of the unit is medium gray. Grain size is very fine sand to silt. Homogenous texture and mineralogy. No obvious cross beds or ostracods. Bone fragments are preserved in the rock. Unit does not react to HCl.

14 7’’ This is a resistant capping unit. Weathered surface is reddish brown, 0.18 m calcareous. Fresh surface is yellowish light gray. Texture is homogenous; grain size is silt. Minerals are mostly light colored. Rough layers are 0.5 to 3 cm thick. Unit thickness is slightly variable in this area. Ostracods present, but no obvious cross beds. Unit reacts upon exposure to HCl.

15 6’ 2’’ This unit includes the UF 19297 upper horizon plant fossil quarry. 1.88 m Surface color is light yellowish tan, while fresh material is pinkish gray

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with lots of sulfur and iron staining and layers of gypsum. Matrix is homogenous and silt sized. It is hard to break and splits in irregular blocks. Just above the plant layer the matrix transitions to a light malachite green color, while all other characters stay the same. Plants are ~2/3 the distance up the unit. Collected part of green layer as a possible tuff (BR-5), but it did not yield any usable dates. Unit coarsens upward into green tuff. Very fine to fine sand grain size. No obvious ostracods or cross beds. Unit does not react to HCl.

16 17’ 10’’ This unit has 4 areas where the rock crops out. The surface sediment is 5.44 m light yellowish gray. The outcropping rock weathers to brownish red, but is medium gray and crystalline on fresh surfaces. Grains are well-sorted, fine to medium sand and subrounded. Matrix is mostly quartz and has some feldspar and rarer dark minerals. Unit is easily identified by its densely packed gastropods (Goniobasis / Elimia). There are also rarer, usually broken bivalve shell fragments. There are also a few bone and turtle shell fragments on the surface. The outcropping ledges are 11-16 cm thick. Clasts look like sand or mineral grains, not ostracods. No obvious cross beds. Some clasts are large, >1 cm in diameter. Some shells (Goniobasis) are >2 cm long. Most clasts are smaller though. Unit reacts strongly to HCl.

17 37’ 8’’ Unit is bluish gray near the base, but quickly transitions to whitish gray. 11.48 m There are no clear layers from here through the vegetated surface (top of the escarpment). Fresh rock is light greenish gray. Matrix is homogenous. Grain size is silt to clay. The top of the unit is capped by a coarser (fine sand) sandstone (tuff, glass possible) that is mostly quartz, some feldspars, and darker minerals. Grains are subrounded. The “tuff” areas are bright white or have bright white spots. Color here (weathered color?) is yellowish gray. Upper plateau is vegetated with desert varnish pebbles from the Wind River Formation. There are also occasional bone fragments mixed in with the pebbles. No obvious cross beds or ostracods. Occasional weak fizz with exposure to HCl, usually no fizz.

Total 224’ 11” 68.56 m Note. Stratigraphically, unit 1 is the oldest at the bottom of the escarpment; unit 17 is the youngest at the top of the section. Colors are representative of my observations and do not correspond to a specific color chart (e.g., Munsell).

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Figure A-1. Complete 40Ar/39Ar data results.

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Figure A-1 continued.

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APPENDIX B INDIVIDUAL LEAF SPECIMEN DESCRIPTIONS

Part I: UF Locality 19404

Morphotype—Toothed 4

19404-61671 (nc, darker leaf)—Leaf fragment microphyllous, full lamina at least notophyllous. Apex missing, base obtuse. Primary venation pinnate; secondaries likely semicraspedodromous. Secondaries with decurrent to mostly excurrent attachment. Secondaries regularly spaced and angled where visible (~45-55° mid-leaf; basal secondaries diverge at ~65° off the primary). Margin likely toothed. Tertiaries opposite percurrent where preserved, although only a few visible. Higher order venation not preserved. Only 2 poorly preserved teeth present, tooth characters cannot be described.

19404-61686 (1)—Microphyllous leaf fragment with both base and apex missing. Margin toothed (serrate). Primary venation pinnate; secondaries semicraspedodromous. Tertiaries mixed percurrent. Higher order venation not preserved. One order of regularly spaced teeth. Four to five teeth per centimeter; sinuses angular. Tooth shape variable CV/CV with pointed apices. Remarks—This specimen looks like the D/E morphotype (e.g., 19297-43693, 43716) from the 19297 quarry in the upper horizon at Blue Rim. It was initially compared with 19404- 61716, but these two specimens seem different based on the size and shape of the teeth and the angle the secondaries diverge from the midvein.

Morphotype—Toothed 5

19404-61715 (68)—Mesophyllous, toothed leaf fragment. Primary venation pinnate; secondaries likely semicraspedodromous. Secondaries with excurrent attachment. Intersecondaries present, parallel to major secondaries, distal course parallel to major secondaries, intersecondaries less than one per intercostal area. Tertiaries percurrent; higher order venation irregular reticulate. Teeth regularly spaced where visible; 4-5 teeth per centimeter. Sinuses rounded; tooth shape CV/CV with some variability to almost ST/ST.

19404-61716 (151)—Notophyllous lamina with base and apex missing. Shape likely elliptic. Symmetry could not be determined. Lamina unlobed and toothed (serrate & crenate). Primary venation pinnate. Secondaries semicraspedodromous. Secondaries evenly spaced and angled (~60-70°) with excurrent to rarely decurrent attachment to the midvein. Intersecondaries present, variable. Tertiaries mixed percurrent (opposite more common), but only observed in a very small section of leaf. Higher order venation not preserved. One order of regularly spaced teeth. Teeth small, ~4 per centimeter. Sinuses slightly angular.

Morphotype—Toothed 13

Species—“Aleurites” fremontensis (Berry) MacGinitie

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19404-61676 (nc)—Leaf fragment. Specimen has two poorly preserved teeth and appears to have scattered dots across surface (Details are a bit hard to discern because of the coarse sediment).

19404-61685 (194)—Marginally attached, petiolate, notophyllous leaf fragment. Petiole over 1.5 mm in width. Base symmetrical, medial symmetry could not be determined. Margin untoothed (where visible). Apex missing; base obtuse and cuneate. Primary venation pinnate or palinactinodromous. Naked basal veins present; seven basal veins. Secondaries with excurrent attachment to the midvein. No higher order venation preserved. Remarks—This specimen can be assigned to the Aleurites morphotype based on the following characters: generally symmetrical about the midvein, an entire base (toothed apex/lobes are not preserved), secondaries arising at opposite or sub-opposite locations, thinner intramarginal, but prominent secondary vein along the margin the basal portion of the leaf, and a stout petiole.

19404-69291 (121)—Incomplete leaf notophyllous. Margin untoothed near base where preserved. Base acute and likely straight. Base not completely preserved, but likely 5 basal veins. Further venation characters could not be determined. Remarks—Leaf surface is covered with pigmented dots, a character common to “Aleurites” fremontensis specimens. The upper part of the leaf that would have teeth is not preserved.

Morphotype—Entire 1: “Star”

19404-61659 (nc)—Notophyllous leaf missing both apex and base. Incomplete length 8.6 cm; width 2.5 cm. Lamina appears asymmetrical in both medial width and basal width. Primary venation pinnate. Secondaries likely brochidodromous, but gauge of vein is very thin near margin. Secondaries regularly spaced and angled (~60°) with excurrent to decurrent attachment to the midvein. Intersecondaries present; approximately perpendicular to midvein, more than 50% of subjacent secondary in length, distal course perpendicular to subjacent major secondary, less than one per intercostal area. Forth order venation forms irregular polygons. Other characters of higher order venation not preserved due to the coarse sediment.

19404-61662 (nc)—Marginally attached, notophyllous lamina. Incomplete length 11 cm, width 3.1 cm for a length to width ratio of 3.55:1. Shape elliptic. Medially symmetric, base may be asymmetrical, but not completely preserved. Lamina unlobed and untoothed. Apex very acute and straight. Primary venation pinnate; secondaries with excurrent attachment and regularly spaced and angled (~60° mid leaf, ~70° base, ~50° closer to apex) where visible. No higher order venation preserved.

19404-61664 (nc, p)—Microphyllous leaf fragment (leaf likely notophyllous) marginally attached and petiolate. Petiole thick—over 2 mm wide. Margin untoothed. Apex missing, base obtuse and convex. Primary venation pinnate. Secondaries uniformly spaced and angled (~55- 60°) with excurrent attachment where visible. Higher order venation not preserved.

19404-61667 (nc)—Marginally attached, petiolate leaf at least notophyllous. Shape elliptic to oblong (no apex). Lamina has slight medial asymmetry and basal insertion asymmetry. Lamina

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unlobed and untoothed. Apex not preserved; base obtuse and convex. Primary venation pinnate; naked basal veins appear to be present. Secondaries brochidodromous. Secondaries diverge from midvein at angles of approximately 60°. Higher order venation preserved in a few small patches, but the specific arrangement could not be determined.

19404-61668 (nc)—Marginally attached, microphyllous leaf fragment. Incomplete length 7.5 cm, width ~2.5 cm wide. Shape elliptic; basal insertion asymmetry. Lamina unlobed and untoothed. Apex missing; base acute, convex on one side, concavo-convex on another side. Primary venation pinnate, secondaries regularly spaced and angled (~50-60°). Higher order venation not preserved.

19404-61671 (nc, lighter leaf)—Poorly preserved leaf fragment, notophyllous. Margin untoothed. Primary venation pinnate. Secondaries regularly spaced and angled (~50-60°) where visible. No higher order venation preserved.

19404-61673 (nc)—Marginally attached leaf fragment, notophyllous. Apex missing, but overall shape appears oblong. Lamina medially symmetric; base incomplete. Primary venation pinnate; secondaries brochidodromous. Secondaries with uniform spacing and angle (~50-70°, most around 60°) with excurrent attachment. Small patch of higher order venation is irregular reticulate.

19404-61676 (nc)—Notophyllous leaf, 10.4 cm long by 3.1 cm wide for an incomplete length to width ratio of 3.35:1. Laminar shape oblong. Medially symmetric; basal symmetry could not be determined. Lamina unlobed and untoothed. Apex and base both acute and likely straight, although not completely intact. Primary venation pinnate; secondaries regularly spaced and angled (~55-70° off primary) with excurrent attachment. Intersecondaries present; perpendicular to midvein. Higher order venation not preserved. Remarks—This hand sample also has Lygodium fragment and a very poorly preserved fragment of a toothed leaf, possibly representative of “Aleurites.”

19404-61677 (nc)—Leaf fragment notophyllous. Neither base nor apex preserved. Lamina unlobed and untoothed. Primary venation pinnate; secondaries regularly spaced and angled (~60°). Secondaries with excurrent attachment. Intersecondaries present, details not preserved.

19404-61680 (nc)—Microphyllous leaf fragment with acute, straight to convex base. Venation pinnate. Secondaries regularly spaced and angled (~50-60°) with excurrent attachment where visible.

19404-61682 (nc)—Leaf fragment notophyllous. Symmetry could not be determined. Lamina unlobed and untoothed. Apex acute and straight; base not preserved. Primary venation pinnate. Secondaries appear regularly spaced and angled (50-60°). Higher order venation not preserved.

19404-61688 (104)—Marginally attached, microphyllous lamina. Length 7.5 cm, width 2.35 cm for a length to width ratio of 3.19:1. Shape elliptic to oblong. Medially symmetric, base asymmetric in width, possibly insertion, but not well-preserved near base. Lamina unlobed, untoothed. Apex acute, straight to acuminate (not complete). Base angle ~90 degrees, base shape

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convex. Primary venation pinnate; secondaries brochidodromous, evenly spaced and angled (~50-65°) with excurrent attachment to the midvein. Higher order venation not preserved.

19404-61692 (88, 89, 90, 91, 92)— 88: Notophyllous leaf fragment with pinnate primary venation and regularly spaced and angled (~50°) secondaries. Higher order venation not preserved. 89: Microphyllous leaf fragment; untoothed where margin visible. Primary venation pinnate; secondaries appear regularly spaced and angled (~50-60°). Higher order venation not preserved. 90: Microphyllous leaf fragment, petiolate and marginally attached. Base appears acute and straight. Thick primary over 1 mm in diameter near base of leaf. Primary venation pinnate; secondaries regularly spaced and angled (~60-75°) where preserved. Intact margin near base untoothed. Faint intersecondary present. 91: Microphyllous leaf fragment, petiolate with thick pinnate primary venation. Secondaries regularly spaced and angled (~50-60°) where visible. 92: Microphyllous leaf fragment has a marginally attached petiole and an obtuse convex base. Primary venation pinnate with regularly spaced and angled secondaries (~55-70°).

19404-61695 (nc)—Marginally attached, mesophyllous lamina. Length 11.9 cm, width 4.6 cm for a length to width ratio of 2.59:1. Laminar shape ovate. Leaf seems slightly asymmetrical in width. Apex acute and straight to acuminate; base obtuse and straight to convex. Lamina unlobed and untoothed. Primary venation pinnate; secondaries regularly spaced and angled (~50° mid leaf, 60 ° in transition zone, ~70° base of leaf) with excurrent attachment. Higher order venation not preserved.

19404-61698 (200)—Mesophyllous leaf fragment. Lamina likely untoothed (but possible tooth), but the margin not clear. Base obtuse and convex, apex missing. Primary venation pinnate. Secondaries regularly spaced and angled (~60-70°) where visible with excurrent attachment. Higher order venation not preserved.

19404-61705 (8)—Notophyllous leaf fragment; unlobed and untoothed. Lamina marginally attached and petiolate with a 2.6 cm long petiole. Apex missing; base convex. Primary venation pinnate. Secondaries regularly spaced and angled (~55-65°) with excurrent attachment to the midvein.

19404-61708 (31)—Microphyllous leaf fragment. Primary venation pinnate with thick primary (>1 mm). Secondaries likely brochidodromous, uniformly spaced and angled (~60°) where visible with excurrent attachment. Faint intersecondary present. Higher order venation not preserved.

19404-61712 (184)—Petiolate, marginally attached (preserved portion of petiole is 10 mm long by 2.5 mm wide, flares away from lamina) lamina. Lamina notophyllous; it may be mesophyllous if not missing apex. Width 3.7 cm, incomplete length 9 cm. Overall shape oblong; medially symmetric. Lamina unlobed and untoothed. Base obtuse and convex; apex not preserved. Primary venation pinnate; secondaries brochidodromous (almost eucamptodromous).

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Secondaries evenly spaced and angled (~60-75°) with excurrent attachment. Higher order venation not preserved.

19404-61720 (77, 78)—Two untoothed leaf fragments. Pinnate primary venation. Secondaries uniformly spaced and angled with excurrent attachment where visible.

19404-61722 (4)—Notophyllous lamina, width 3.2 cm. Slight width asymmetry. Shape elliptic to oblong. Lamina unlobed and untoothed. Apex and base not preserved. Primary venation pinnate; secondaries brochidodromous. Secondaries regularly spaced and angled (~50-65°) with excurrent attachment to the midvein. Higher order venation not preserved.

19404-69290—Notophyllous leaf fragment; missing base and apex. Margin untoothed. Primary venation pinnate, secondaries likely brochidodromous—thin gauge veins loop near margin. Secondaries with excurrent attachment to the midvein and regular spacing and angle (~60°).

19404-69291 (120)—Incomplete leaf microphyllous. Shape appears elliptic, medially symmetric, base not preserved. Lamina unlobed and untoothed. Apex acute; base not preserved. Primary venation pinnate. Secondaries regularly spaced and angled (~50-60°) where visible with excurrent attachment. Higher order venation not preserved.

Morphotype—Entire 2: “Triangle”

19404-61674 (nc)—Marginally attached leaf at least notophyllous. Laminar shape elliptic or oblong. Base appears asymmetrical. Apex missing; base acute and convex. Lamina unlobed and untoothed. Primary venation pinnate; secondaries brochidodromous. Secondaries irregularly spaced with a consistent angle (~60° mid leaf, increases to ~75° in basal portion of leaf) to the midvein. Secondaries with excurrent attachment to the midvein. Intersecondaries present, close to perpendicular. Intersecondary distal course perpendicular to subjacent major secondary. Intersecondary frequency less than one per intercostal area. Tertiaries mixed percurrent, irregular. Higher order venation irregular reticulate where visible.

19404-61689 (12)—Leaf fragment microphyllous; margin untoothed. Apex missing; base convex. Primary venation pinnate; secondaries brochidodromous. Secondaries regularly spaced and angled (~60°) where visible with excurrent to decurrent attachment to the midvein. Intersecondaries present, perpendicular to midvein. Higher order venation not well-preserved.

19404-61690 (100? 108?)—Marginally attached, microphyllous leaf fragment. Symmetry cannot be determined. Lamina unlobed and untoothed. Apex missing; base appears acute and slightly convex. Primary venation pinnate with a thick primary (~1 mm). Secondaries with excurrent attachment. Secondaries branch in a “Y” shape as they approach the margin. Higher order venation not preserved.

19404-61699 (42)—Lamina notophyllous. Base and apex missing. Shape likely elliptic. Primary venation pinnate; secondaries brochidodromous. Secondary spacing and angle (~65°) consistent with excurrent attachment. Intersecondaries present, parallel to major secondaries, less than one per intercostal area. Tertiaries mixed percurrent, mostly opposite with an obtuse angle to the

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midvein. Epimedial tertiaries perpendicular to midvein. Higher order venation appears irregular reticulate, but is poorly preserved and only present in a small portion of the leaf.

19404-61700 (72)—Leaf fragment notophyllous. Shape appears elliptic, but lamina incomplete. Lamina unlobed and untoothed. Apex and base missing. Primary venation pinnate; secondaries brochidodromous. Secondaries uniformly spaced and angled (~50-70°) with excurrent attachment. Intersecondaries present, details not preserved. Higher order venation not preserved.

19404-61708 (29)—Notophyllous leaf fragment, lamina at least mesophyllous. Width 4.7 cm. Shape likely elliptic to oblong. Lamina unlobed and untoothed; apex and base missing. Primary venation pinnate. Secondaries brochidodromous, regularly spaced and angled (~55-65°) with excurrent attachment. Intersecondaries present, but very faint. Higher order venation not preserved.

Morphotype—Entire 5: “Long rectangle = Cedrela Star”

19404-61664 (nc, lighter leaf with no petiole)—Microphyllous leaf fragment with no base or apex. Margin untoothed. Primary venation pinnate; secondaries regularly spaced and angled (~70-80°) with excurrent attachment where visible. Intersecondaries present, perpendicular to midvein. Higher order venation not preserved.

19404-61684 (82)—Marginally attached, notophyllous leaf fragment. Margin untoothed. Apex missing; base obtuse, possibly rounded or cordate. Primary venation pinnate; secondaries possibly brochidodromous. Secondaries diverge at angles close to 90°. Intersecondaries present. No other details of higher order venation visible.

19404-61707 (133)—Marginally attached lamina, mesophyllous. Incomplete length 10.8 cm, width 4.9 cm. Shape appears elliptic to oblong. Lamina appears symmetric, but incomplete. Lamina unlobed and untoothed. Apex missing, base obtuse and convex. Primary venation pinnate, agrophics absent. Secondaries brochidodromous. Secondaries regularly spaced with angle smoothly increasing proximally (~55-90°). Secondaries with excurrent attachment to the midvein. Intersecondaries present, specific features not preserved. Higher order venation not preserved.

Morphotype—Entire 7: “Angular parallelogram”

19404-61665 (nc)—Leaf fragment notophyllous. Lamina untoothed. Likely primary pinnate. Prominent pair of acute (~20° from midvein) basal secondaries present. No other secondaries diverge near base of leaf. Higher order venation not preserved.

19404-61721 (7)—Marginally attached, microphyllous lamina. Ovate to elliptic in shape; symmetric medial symmetry. Lamina unlobed with an untoothed margin. Acute apex, likely straight (only partially preserved); base acute. Primary venation likely palmate (base not preserved). Secondaries appear brochidodromous. Tertiaries mixed percurrent, opposite more frequent. Fourth and fifth order venation irregular reticulate.

531

Morphotype—Entire 8: “Y”

19404-61701 (185)—Untoothed leaf fragment, notophyllous. Apex acute (very narrow) and straight; base absent. Primary venation pinnate; secondaries brochidodromous. Some secondaries branch approximately halfway to the margin. Possible intersecondaries, tertiaries percurrent in small part of leaf where visible. Higher order venation not preserved.

19404-61704 (84)—Notophyllous leaf fragment, untoothed. Primary venation pinnate; secondaries uniformly angled (~60°) and spaced where visible with excurrent attachment. Some secondaries “Y” branch near margin. Intersecondaries present, perpendicular to midvein. Higher order venation not preserved.

19404-61712 (183)—Marginally attached, microphyllous lamina. Width is 2.4 cm; shape elliptic. Medially and basally symmetric. Lamina unlobed and untoothed. Apex missing, base acute and slightly convex. Primary venation pinnate; secondaries brochidodromous. Secondaries with uniform spacing and angle (~50-60°) with excurrent attachment. Secondaries branch in a “Y” pattern about 2/3 of way to margin. Intersecondaries present, perpendicular to midvein. Intersecondary distal course perpendicular to basiflexed. Some spaces between secondaries with more than one intersecondary, but intersecondaries not well-preserved throughout leaf. Tertiary pattern not clear. Higher order venation irregular reticulate. Areolation well-developed. Freely ending veinlets visible.

Morphotype—Entire 11: “Sguiggly box”

19404-61708 (30)—Microphyllous leaf fragment, shape appears elliptic, but apex and base missing. Primary venation appears pinnate. Secondaries brochidodromous. Secondaries widely spaced with somewhat uniform spacing and angle (narrower divergence angle toward the base ~40-45°, wider divergence toward the apex ~70°) where visible. Secondaries with excurrent to decurrent attachment. Intersecondaries not observed. Tertiaries percurrent where visible. Higher order venation not preserved.

19404-61710 (202)—Untoothed leaf fragment. Secondaries likely brochidodromous. Tertiaries mixed percurrent. Remarks—Secondaries are more widely/irregularly spaced than the Entire 1: “Star” morphotype.

Morphotype—Entire 13: “Loopy Squiggle”

19404-61672 (nc)—Marginally attached, notophyllous lamina. Incomplete length 8.5 cm, width ~5 cm for a length to width ratio of 1.7:1. Laminar shape ovate. Lamina appears symmetric but not completely preserved in medial or basal areas. Lamina unlobed and untoothed. Apex acute and straight; base obtuse and straight where visible. Primary venation pinnate; simple agrophics present. Major secondaries brochidodromous; minor secondaries brochidodromous. Marginal secondary present. Major secondaries regularly spaced and angled (~40-60°) with excurrent attachment. Intersecondaries not observed. Tertiaries mixed percurrent where visible with an

532

obtuse angle to the midvein. Exterior tertiaries looped. Higher order venation irregular reticulate where visible.

19404-61703 (161, leaf on top with margin)—Microphyllous leaf fragment with no apex or base. Margin untoothed. Primary venation likely pinnate; secondaries brochidodromous. Tertiaries faint, likely mixed percurrent. Higher order venation not preserved. Remarks—Secondaries are much more regularly and evenly spaced in this morphotype than the other similar types from the 19404 locality.

“Dicots”: Not assigned to morphotype (NATM)

19404-61681 (nc)—Leaf fragment microphyllous, full blade likely notophyllous. Lamina untoothed. Apex acute; base missing. Primary venation pinnate; secondaries appear brochidodromous, but very faintly preserved. Remarks—This specimen is too poorly preserved and incomplete to morphotype.

19404-61714 (19)—Leaf fragment microphyllous, but complete lamina at least notophyllous. Lamina unlobed and untoothed. Neither apex nor base preserved. Primary venation pinnate; secondaries regularly spaced and angled (~60°) along midvein where preserved with decurrent attachment. Patches of reticulate higher order venation preserved, but overall arrangement not clear. Remarks—Not assigned to morphotype due to lack of apex, base, and margin.

19404-61714 (20)—Poorly preserved leaf fragment with likely marginal attachment. Fragment at least microphyllous. Neither apex nor base preserved. Primary venation pinnate; secondaries regularly spaced and angled (~60°). Higher order venation not preserved. Remarks—Not assigned to morphotype due to lack of apex, base, and margin.

Monocots

19404-61666—Thick parallel veins about 1.5 mm apart. Thinner gauge parallel veins in- between.

Non-Angiosperm

Lygodium Swartz—19404-61669 Asplenium L.—19404-61669 Remarks—Representatives of both of these genera are also found in the Kisinger Lakes site in northwestern Wyoming and in the Green River Formation (MacGinitie, 1969; MacGinitie, 1974).

Part II: Dicotyledonous Leaf Morphotypes from the Lower Horizon

Toothed

Morphotype HT

533

15761-43043—Lamina with marginal attachment; petiole not preserved. Lamina notophyllous (7.7 cm long by 2.9 cm wide). Symmetry could not be determined. Lamina unlobed and toothed (serrate). Apex acute; straight to acuminate in shape. Base ~90° and cuneate in shape. Primary venation pinnate; secondaries c.f. semicraspedodromous, but their interaction with the margin not preserved. Secondaries track very close to the leaf margin. Secondaries with regular spacing and a uniform angle to the midvein (30-40° between secondary and midvein in apical direction). Major secondary attachment to midvein excurrent. Higher order venation not preserved. Teeth regularly spaced with one order; ~4-5 teeth per centimeter. Shape of sinuses unclear. Teeth generally CV/CV in shape. Principle vein present.

Morphotype VCT

15761N-43924 (15, cf. VCT)—Thick primary; regularly spaced frequent secondaries. Intersecondaries present.

15761N-43936 (cf. VCT)—Small fragment. Similar to VCT, but appears to have a broader base, less asymmetrical, petiole expands away from lamina, one or two teeth are preserved and they look reasonably similar to other VCT teeth.

15761N-43941 (cf. VCT)—Only center portion of lamina preserved; no apex or base present. Regular secondaries, likely intersecondaries present. Lots of holes—possible insect damage. Similar to specimen 15761N-61414. A few of the secondaries “Y” (branch) as they head toward margin.

15761N-43999—Petiolate lamina with marginal attachment, notophyllous. Length to width 3.24:1. Shape likely elliptic. Medial and base symmetrical to slightly asymmetrical. Unlobed; margin untoothed near base where preserved. Apex acute, straight. Base ~90°, convex shape. Venation pinnate; one basal vein. Agrophic veins absent. Secondaries loop and branch near margin, but not enough is preserved to classify. Interior secondaries absent. Major secondary spacing slightly irregular; major secondary angle to midvein has one pair of acute basal secondaries. Major secondary attachment to midvein excurrent. Intersecondaries present, perpendicular to midvein, less than 50% of subjacent secondary, branching, and less than one per intercostal area. Tertiaries mixed percurrent, obtuse angle to midvein. Tertiary vein angle generally consistent over the surface of the lamina. Epimedial tertiaries mixed percurrent, course perpendicular to midvein. Exterior tertiaries looped. Quaternaries irregular reticulate. Higher order venation not well-preserved.

15761N-57671 (cf. VCT)—Petiole 1.4 cm long by 1.7 mm wide. Lamina untoothed. Apex missing; base acute and cuneate. Thick, pinnate primary. Naked basal veins present; they are a thinner gauge than the secondaries. Secondaries semicraspedodromous. Possible intersecondaries (not in all intercostal spaces), some may be tertiaries. Secondaries slightly irregularly spaced; angle to midvein of secondaries consistent, except the basal pair slightly more acute. Excurrent attachment of secondaries to the midvein. Tertiaries mixed percurrent. Higher order venation not preserved.

534

15761N-61414 (cf. VCT)—Multiple leaves on this slab; this one is toothed and looks like 15761N-43941. Pinnate primary venation, regular secondaries. Teeth with angular sinuses. Slightly CV/CV tooth shape. No base or apex preserved. Higher order venation not well- preserved. There is also a different entire margined specimen (on the same hand sample) that is not well-preserved, but has “Y” splitting of two the secondaries that are visible.

Morphotype SR

15761N-43976—Partial blade, microphyllous. Apex obtuse and convex. Base not preserved. Pinnate primary venation. Secondaries semicraspedodromous. Marginal secondary present. Visible secondaries have a decurrent attachment to the midvein. Irregular reticulate tertiaries. Quaternary and quinternary vein fabric irregular reticulate. Margin crenate. Teeth irregularly spaced. One order of teeth with ~1 tooth per centimeter. Sinuses rounded; tooth shape is not well-defined but falls closest to CC/CV. Principal vein present in the tooth, terminates slightly on the distal flank. Tooth apex cassidate.

15761N-43992—This specimen looks lobed as opposed to being two leaflets. The right side has continuation of primary vein like Serjania rara. The secondaries are very faintly preserved in a few places, but no other higher order venation is preserved. The shape and other features are dependent on whether this specimen is designated as two leaflets or a single lobed lamina (the latter accepted here). This specimen was originally treated as two tiny legume leaflets in the field census (157, 158).

15761N-61377—Partial, notophyllous lamina. Preserved length 5.9 cm; width 4.0 cm. Laminar shape elliptic. Medial and basal symmetry unknown. Palmately lobed. Apex of preserved lobe acute and straight. Base convex where preserved. Primary venation actinodromous. Higher order venation not preserved. Margin serrate. Teeth absent near the base and on the interior margins of the lobes. One order of teeth; one to two teeth per centimeter on the sections of leaf that preserve teeth. Sinuses angular. Tooth shape variable and ranges from CV/CV to ST/ST. The main vein in the tooth protrudes slightly at the tooth apex. Remarks—This partial specimen lacks its right side (ripped/torn away). My guess is that this leaf is three lobed and only the left and part of the center is preserved. This specimen is most likely a large terminal leaflet of the Serjania rara morphotype.

Morphotype AF

15761-57658 (cf. AF)—This fragment lacks a clear margin and a clear point of orientation. There are dots scattered on the surface, which indicates either Aleurites fremontensis or Goweria bluerimensis. The secondaries branch regularly in A. fremontensis and occasionally in Goweria. Because the venation is a bit more irregular, this fragment is more likely to be Aleurites.

18288-56285—Petiolate leaf with marginal attachment (petiole 5.8 cm long by 3+ mm wide). Lamina macrophyllous. Length and width both >15cm. Shape elliptic. Basally and medially symmetric. Lamina palmately lobed and serrate. Apex acute and likely straight (but not completely preserved). Base obtuse and rounded in shape. Primary venation palinactinodromous;

535

naked basal veins present. Five basal veins present (not including marginal veins). Simple agrophics present. Major secondaries semicraspedodromous; minor secondaries semicraspedodromous. Marginal secondary, but only in basal portion of leaf. Major secondaries regularly spaced with a uniform angle to the midvein. The major secondary attachment to the midvein excurrent; intersecondaries not preserved. Tertiaries faintly preserved, generally opposite percurrent (occasionally alternate), convex to chevron in shape. Higher order venation poorly preserved; likely reticulate. Teeth regularly spaced (where present, not near base); one order of teeth with ~4 teeth per centimeter. Teeth surprisingly small for the size of the leaf. Sinuses rounded; tooth shape ~ST/ST (preservation poor); principle vein present in each tooth.

Morphotype GBT

15761N-61470 (130, ?, p, pp)—Preserved portion of the petiole 1.3 cm long by 1 mm wide. Venation poorly preserved. Teeth bulbous. Remarks—This specimen has intermediate features between morphotypes GBT and PC. The tooth shape and dark preservation matches morphotype GBT. However, the narrower base with only 3 visible major veins originating near the base (rather than 5) is more similar to PC.

19337-61592—Marginally attached, notophyllous lamina. Length 7 cm by 4.2 cm wide. Lamina ovate to elliptic in shape and medially and basally symmetric. Unlobed lamina with toothed margin (serrate). Apex acute and straight; base obtuse and convex. Primary venation basal to suprabasal actinodromous to acrodromous. Naked basal veins not visible; 5 basal veins. Simple agrophic veins. Major secondaries ~semicraspedodromous. Higher order venation not preserved. Teeth absent near base. Sinuses rounded, tooth shape CV/CV. Principle vein present in each tooth. Other tooth characters obscured.

Morphotype TDA/PS

15761N-57410—Medial symmetry varies from symmetrical to slightly asymmetrical. Lamina unlobed and toothed (crenate and serrate). Both the apex and base missing, but appear acute. Primary venation pinnate; secondaries semicraspedodromous. Secondaries diverge at close to 90° from the primary. Secondaries diverge from the midvein at more acute angles in the basal part of the leaf, but are not all preserved. Secondaries irregularly spaced with excurrent attachment to the midvein. Intersecondaries present; perpendicular to the midvein. Intersecondaries common in the preserved section of leaf. Tertiaries faintly preserved and either alternate percurrent or reticulate. Higher order venation not preserved. One order of regularly spaced teeth; ~3 teeth/cm. Principal vein present in each tooth with marginal termination at the nadir of the superjacent sinus. The major accessory vein in each tooth convex in relation to the principal vein. Sinuses more or less angular; tooth shape CV/CV.

15761N-57652—Lamina petiolate with marginal attachment. Lamina notophyllous—this specimen 8.8 cm long by ~3 cm wide for a length to width ratio of 2.93 :1. Laminar shape elliptic; symmetrical to slightly asymmetrical. Lamina toothed with serrate and crenate protrusions. Apex acute and straight, base acute and cuneate. Three basal veins present. Primary venation pinnate; secondaries semicraspedodromous. Marginal secondary present. Secondaries

536

irregularly spaced with one pair of acute basal secondaries with an excurrent attachment to the midvein. Intersecondaries present, perpendicular to the midvein. Intersecondaries fork and branch toward the base and apex and connect with the secondaries. Intersecondaries slightly >50% of the length of the subjacent secondary. Higher order venation reticulate. One order of teeth, semi-regular with ~2 teeth/cm. Sinuses angular to semi-rounded. Teeth CV/CV in shape. Principle vein present with marginal termination; termination between the distal flank and the nadir of the superjacent sinus.

15761S-57883—Lamina with marginal attachment; petiolate. Partially preserved petiole 0.5 cm long by 1 mm wide. Lamina microphyllous and approximately 3.4 cm long by 1.0 cm wide. Medially symmetrical; base asymmetrical in width. Lamina unlobed and toothed. Apex acute, straight; base acute, convex. Primary venation pinnate with one basal vein. Possible intramarginal secondary. Secondaries semicraspedodromous, irregularly spaced with one pair of acute basal secondaries. Secondaries with excurrent attachment to the midvein. Intersecondaries may be present (preservation poor). Tertiaries appear irregular reticulate. Higher order venation not preserved. Teeth small; regularly spaced, but absent from base of leaf. Where present, one order of approximately 8 teeth/cm with rounded to angular sinuses. Tooth shape CV/CV. Venation in the tooth not preserved.

Morphotype CBT

15761S-57828—Lamina mostly complete and petiolate with marginal attachment. Lamina toothed, microphyllous. Base obtuse and convex. Primary venation pinnate with approximately three basal veins (composed of the primary and two secondaries). Secondaries craspedodromous (terminate in each tooth). Simple agrophics present; minor secondaries craspedodromous. Secondaries regularly spaced with a uniform angle to the midvein and excurrent attachment. Intersecondaries and other higher order venation not preserved. Teeth generally regularly spaced. Two sizes of teeth present. The larger teeth found at the end of each major secondary. The smaller teeth, present near the base of the leaf, found at the end of each minor secondary (the minor secondaries branch off the first major secondary). Sinuses angular; teeth convex/convex. Principle vein present, terminates at the margin and varies in position from terminating at the tooth apex to the distal flank.

15761S-57829—Both the base and apex missing. The preserved portion of the leaf notophyllous. Agrophics simple; major and minor secondaries craspedodromous. Secondaries have a subopposite attachment to the midvein. Secondaries regularly spaced with a uniform angle to the midvein and excurrent attachment to the midvein. Intersecondaries present; intermediate in form between parallel to major secondaries and perpendicular to the midvein. Intersecondary length <50% of subjacent secondary. Distal course of intersecondary approximately perpendicular to the subjacent major secondary. Usually one intersecondary per intercostal area. Tertiaries not well-preserved, likely percurrent. Higher order venation not preserved. Teeth regularly spaced (in the middle of the leaf; teeth smaller near the base). Approximately two orders of teeth present with ~2 teeth/cm in the middle of the lamina. Sinuses angular, tooth CV/CV occasionally varying to FL/CV. Principle vein present with marginal termination.

537

Morphotype TT

19337-61591—Marginally attached lamina, notophyllous. Shape ovate to elliptic although only partially preserved. Basal insertion asymmetrical. Lamina likely unlobed. Margin toothed (serrate). Apex not preserved. Base slightly obtuse; shape convex on one side and concavo- convex on the other side. Primary venation pinnate with one basal vein. Agrophics absent; secondaries semicraspedodromous. Secondaries semi-regularly spaced with a uniform angle to the midvein; attachment to the midvein excurrent. Intersecondaries present; parallel to major secondaries. Length of intersecondaries more than 50% of subjacent secondary. Intersecondary reticulating and contacting major secondary loop where well-preserved. Less than one intersecondary per intercostal area. Tertiaries mixed percurrent, but not well-preserved. Higher order venation not well-preserved. Teeth regularly spaced with two orders, 2-3 teeth per centimeter. Sinuses angular; tooth shape ST/ST. Principle vein present with marginal termination at the apex of the tooth.

Toothed: Not assigned to morphotype (NATM)

15761N-43926—Mostly opposite percurrent straight tertiaries. Secondaries branch and enter teeth. Teeth CV/CV with angular sinuses.

15761N-57644—Only part of the apical portion of the lamina preserved. Lamina toothed; apex acute and appears straight. Primary venation pinnate. Secondaries appear semicraspedodromous with excurrent attachment to the midvein. Intersecondaries may be present. Higher order venation is reticulate. Teeth small; ~3/cm with semi-regular spacing. One order of teeth with angular sinuses. Teeth rounded and CV/CV in shape. Remarks—Looks different than the other morphotypes from this horizon based on the teeth, but it is too fragmentary and poorly preserved to create its own morphotype.

Untoothed

Morphotype TRB

15761-55187—Marginally attached petiolate lamina (petiole is ~1.3 mm wide by 1.7 cm long). Lamina microphyllous (on border with notophyllous). Length not preserved; width is 2.5 cm. Shape elliptic. Medially symmetry just slightly asymmetrical; basal width asymmetry. Lamina unlobed and untoothed. Apex not preserved; base obtuse and convex to rounded in shape. Strong pinnate primary; one basal vein. Agrophics absent. Major secondaries interaction with the margin not clear—possible eucamptodromous. Interior secondaries absent; perimarginal vein not observed. Secondaries irregularly and distantly spaced except for a few closer veins near the base. Secondary angle to midvein ~uniform. Secondaries with excurrent attachment to the midvein. Intersecondaries present; parallel to major secondaries. Intersecondary length less than 50% of subjacent secondary; distal course not clear; frequency less than one per intercostal area. Tertiaries ~irregular reticulate. Higher order venation not well-preserved. Freely ending veinlets ~present.

538

15761S-57840—Marginally attached petiolate lamina (petiole is ~1 mm wide by 1.1+ cm long). Leaf microphyllous (incomplete length 4.6 cm by 1.9 cm wide for a length to width ratio of 2.42:1). Shape ovate; medially symmetrical, base slightly asymmetrical. Lamina unlobed and untoothed. Apex acute; shape convex to straight (only partially preserved). Base obtuse; convex to rounded. Venation pinnate with one basal vein. Secondaries brochidodromous to eucamptodromous (very hard to see near margin). Secondary spacing somewhat irregular with secondary angle abruptly increasing proximally with excurrent attachment to the midvein. Intersecondaries present; close to parallel to the major secondaries and generally less than 50% of the subjacent secondary. Intersecondary course reticulating or ramifying with approximately one per intercostal area (however preservation is poor). Tertiaries not well-preserved, but appear reticulate.

Morphotype BTBP

15761N-43945—Only upper half of lamina preserved. Lamina mesophyllous. Shape and asymmetry not preserved. Apex acute and straight. Primary venation pinnate; primary thick. Secondary venation brochidodromous. Fimbrial vein present. Major secondary attachment to midvein excurrent. Angle of secondaries to midvein—lowest pair close to 90°, but abruptly transitions to more acute. Intersecondaries present; perpendicular to midvein (these may be tertiaries, the preservation is very poor). Tertiaries possibly alternate percurrent. Some higher order venation reticulate; details not preserved.

15761N-43948—Only part of upper half of lamina preserved. Primary venation pinnate. Secondaries brochidodromous; similar spacing and angle in the section of the leaf that is preserved with excurrent attachment to the midvein. Possible intersecondary present. Tertiaries alternate percurrent where preserved. Higher order venation reticulate.

15761N-43995 (18)—Lamina petiolate with marginal attachment. Lamina mesophyllous. Length to width ratio 2.1:1 (length 12.5 cm, width 5.9 cm). Medial symmetry slightly asymmetrical. Unlobed, untoothed lamina. Apex acute, straight. Base obtuse, truncate transitioning to convex in shape. Petiole 3.2 cm long, 3 mm wide. Primary venation pinnate. Major secondaries brochidodromous. Interior secondaries absent. Secondary spacing regular with a uniform secondary angle to midvein (90° or slightly less). Major secondary attachment to midvein excurrent. Intersecondaries present; perpendicular to midvein, less than 50% of subjacent secondary, less than one per intercostal area. Tertiaries alternate percurrent. Higher order venation not preserved. Remarks—It is difficult to distinguish intersecondaries and tertiaries on this specimen.

15761N-57665—Upper half of lamina only; base missing. Apex acute, very narrow at apex, ~acuminate. A few of the secondaries fork in the middle of the lamina as they travel toward the margin. A few strong intersecondaries present; they “T” at the end with strong tertiaries coming off of that on either side. Higher order venation well-preserved, close to orthogonal mesh, areoles well-developed.

539

15761N-61375 (310)—Missing apex and base. Asymmetrical medial symmetry—2.1 cm left half width, 3.3 cm right half width. Very dark preservation, but the higher order venation looks similar to other specimens of this morphotype. Some of the tertiaries near the midvein originate on the lower side of a secondary near the junction with the midvein and then travel down and toward the margin before joining with the secondary below. Remarks—Although intersecondaries are not obvious on this specimen and the medial tertiary arrangement is slightly different, the venation has similar patterns to other specimens of this morphotype.

15761N-61383 (199)—Petiole marginally attached, 2.4 cm long. Lamina mesophyllous. Incomplete length is 11 cm, width is 5 cm for a ratio of 2.20:1. Shape ovate. Leaf symmetrical (based on what is preserved) and unlobed and untoothed. Partially preserved apex acute, straight. Base obtuse to reflex and concavo-convex in shape. Primary venation pinnate. Naked basal veins present. Two to three basal veins. Agrophics absent. Secondaries brochidodromous. Interior secondaries absent. Perimarginal vein absent. Major secondaries irregularly spaced. Secondary angle smoothly and gradually increasing proximally. Secondaries with decurrent attachment near the base of the leaf, otherwise excurrent. Intersecondaries present; mostly parallel to major secondaries. Intersecondaries slightly more than 50% of subjacent secondary. Distal course of intersecondary perpendicular to a subjacent major secondary. Frequency of intersecondaries one to two per intercostal area. Tertiaries alternate percurrent to irregular reticulate. Epimedial tertiaries reticulate; exterior tertiaries looped. Quaternaries and quinternaries irregular reticulate. Areoles present, good development. Freely ending veinlets present; appear two or more branched, likely dichotomous. Marginal ultimate venation appears looped.

15761N-61393—Leaf fragment. Thick primary; some intersecondaries. Tertiaries mixed percurrent to irregular reticulate. Irregular reticulate fourth and fifth order venation. Areolation present, good development. Freely ending veinlets present, mostly with two branches, likely dichotomous.

15761N-61419 (226)—Part of lower half of lamina preserved, original intact leaf likely quite large. Secondaries diverge at close to 90° with excurrent attachment. Intersecondaries present. Higher order venation irregular reticulate, similar to other specimens of this morphotype.

15761N-61421 (221)—Only part of left half of lamina preserved. Lamina unlobed and untoothed. Primary venation pinnate; major secondaries brochidodromous. Secondaries with excurrent attachment to the midvein. Intersecondaries present, perpendicular to midvein. Intersecondary distal course perpendicular to a subjacent major secondary. Tertiaries alternate percurrent to irregular reticulate. Epimedial tertiaries reticulate, where preserved. Exterior tertiaries looped. Higher order venation looks irregular reticulate.

15761N-61423—Lamina microphyllous, elliptic, unlobed, and untoothed. (Part of both base and apex missing). Primary venation pinnate; secondaries brochidodromous. Secondaries with excurrent attachment to the midvein. Intersecondaries present. All higher order venation irregular reticulate. Exterior tertiaries looped. Areolation present, good development. Freely ending veinlets present. Marginal ultimate venation looped.

540

15761N-61465 (153)—Petiolate lamina with marginal attachment. Notophyllous, incomplete length 6.2 cm (apex missing); width 4.2 cm. Shape ovate. Slight medial and basal asymmetry, but the leaf also slightly squished. Lamina unlobed; margin untoothed. Apex not preserved; base obtuse, convex to rounded. Primary venation pinnate. Basal veins obscured. Agrophics absent. Secondaries brochidodromous (margin damaged in most places). Interior secondaries absent. Major secondary spacing regular with a uniform angle to the midvein. Secondaries with an excurrent attachment to the midvein. Intersecondaries present, not as obvious as other specimens of this morphotype. Intersecondaries perpendicular to midvein, distal course close to perpendicular to subjacent major secondary. Intersecondary frequency less than one per intercostal area. Tertiaries alternate percurrent. Alternate percurrent epimedial tertiaries, generally perpendicular to midvein. Irregular reticulate quaternaries. Irregular reticulate fifth order venation. Areoles present with good development. Freely ending veinlets present; most with two or more branches. Freely ending veinlet terminals may be tracheoid idioblasts.

15761N-61470—Only part of lower portion of leaf preserved; no apex, base, size or shape characters available. Secondary veins with excurrent attachment to midvein. Intersecondary visible. Tertiaries alternate percurrent. Irregular reticulate quaternaries and quinternaries. Areolation present, good development. Freely ending veinlets present, mostly with 2 or more branches.

15761N-61477—Fragment of large leaf. Venation pinnate; secondaries brochidodromous. On the part of the leaf preserved, the variation of the major secondary angle to the midvein relatively consistent, but the spacing irregular. Excurrent attachment of secondaries to midvein. Intersecondaries present; perpendicular to the midvein. Usually one intersecondary per intercostal area; possibly two, but poorly preserved. Higher order venation not preserved.

15761N-61482—Small fragment, but well-preserved. Pinnate primaries; brochidodromous secondaries. Secondaries with a consistent angle to the midvein; excurrent attachment and irregularly spaced. Intersecondaries present. Higher order venation well-preserved. Tertiaries alternate percurrent, possibly varying to irregular reticulate. Exterior tertiaries looped. Fourth and fifth order venation irregular reticulate. Areolation present, good development. Freely ending veinlets present, mostly with two or more branches.

15761N-61491 (179)—Upper half of large leaf preserved. Unlobed, untoothed. Apex acute. Primary venation pinnate. Secondaries brochidodromous. Secondaries irregularly spaced; excurrent attachment to the midvein. Intersecondaries present, perpendicular to midvein. Tertiaries variable, mixed to alternate percurrent to irregular reticulate. Irregular reticulate higher order venation.

15761N-61495 (131)—Lamina mesophyllous, unlobed, and untoothed. Apex acute, straight to acuminate. Pinnate primary venation; secondaries brochidodromous. Interior secondaries absent; fimbrial vein present (tertiary gauge). From preserved section—secondaries regularly spaced with a uniform angle to midvein; secondaries with excurrent attachment to the midvein. Intersecondaries present; close to perpendicular to midvein. Intersecondaries more than 50% of

541

subjacent secondary with a distal course perpendicular to a subjacent major secondary. Tertiaries alternate percurrent to irregular reticulate. Exterior tertiaries looped. Higher order venation irregular reticulate. Areolation present, good development. Freely ending veinlets present, mostly with two or more branches.

15761S-57832—Specimen has the same fine orthogonal mesh and irregular intersecondaries/epimedial tertiaries as other specimens of this morphotype.

15761S-57872—Apex and part of left side of lamina not preserved. Base rounded. Petiole preserved; 2+ mm wide, at least 2.7 cm long. Two veins on each side that diverge right near the base at angles close to 90°, other secondaries diverge at smaller angles. Higher order venation a fine mesh; freely ending veinlets present, areoles well-developed.

15761S-57873—Obtuse, rounded base; two sets of secondaries near base, shorter that diverge at close to 90° off primary. Freely ending veinlets preserved.

Morphotype BTY

15761-55200—Partial petiole present, ~1 mm wide. Base reflex, slightly cordate, only lower half of lamina preserved; likely elliptic because lamina broadens away from base. Short, poorly developed ~horizontal vein may be present in epimedial area, but not an intersecondary. Secondaries excurrent with a regular spacing and angle. Tertiaries regular, opposite percurrent (rarely alternate percurrent). Tertiary course slightly bent/curved from straight in various ways. Secondaries branch near margin forming a couple small arcs/loops with percurrent secondaries near margin originating off secondary above. Higher order venation not well-preserved.

15761N-43996 (40, 24)—Lamina larger than mesophyll—at least macrophyll (but it is difficult to estimate the full size of this incomplete leaf). Primary venation appears pinnate. The interaction of the secondaries with the margin not preserved. Where preserved, secondary spacing somewhat irregular. Secondary angle to midvein uniform (middle portion of leaf preserved); major secondary attachment to midvein excurrent. No obvious intersecondaries. Tertiaries mostly opposite percurrent; a few alternate. Course of percurrent tertiaries sinuous. Epimedial tertiaries opposite percurrent, perpendicular to the midvein, and the distal course of the epimedial tertiaries parallel to the intercostal tertiaries (bend down toward base of the leaf). Quaternaries and quinternaries regular/irregular reticulate. Areolation present, good development. Freely ending veinlets present. Remarks—Census number 24 is the base of same leaf as census 40.

15761N-57657—Base acute; secondaries branch near margin with tertiaries forming the end of the loop in the same way they do on specimen UF 15761-55200. Many epimedial tertiaries arise at ~90 degrees on primary and bend down and hit secondary below as common in specimen UF 15761N-43996. Tertiaries opposite percurrent, where visible. Higher order venation not well- preserved. Remarks—Characters match those of BTY, but this specimen has an intersecondary (a small one near the apex). Generally, intersecondaries are absent in BTY and present in BTBP.

542

15761N-61417—Left lower half of leaf preserved. Petiole marginally attached; lamina mesophyllous. Margin untoothed. Base obtuse; visible portion cuneate. Primary venation pinnate; agrophics absent. Secondaries brochidodromous; interior secondaries absent. No clear perimarginal vein; looks like looping tertiaries and higher order venation along margin. Uniform major secondary angle to midvein with excurrent attachment. Intersecondaries not observed. Tertiaries mixed percurrent, more alternate. Where applicable, percurrent tertiaries have a straight to sinuous course. Angle of tertiaries to midvein obtuse. Epimedial tertiaries mixed percurrent, more opposite. Course of percurrent epimedial tertiaries generally perpendicular to the midvein with distal/exmedial course basiflexed. Exterior tertiaries looped. Quaternaries alternate percurrent to semi-regular reticulate. Quinternaries semi-regular reticulate. Areoles present, good development. Freely ending veinlets present; mostly with two or more branches—likely dichotomous. Marginal ultimate venation looped. Remarks—This specimen was grouped with BTY and in parts of the lamina it really looks like BTY, but in other places it has a few BTBP characters.

“Morphotype BT”

Specimens with similarities to the BT (BTBP, BTY, BTOS) morphotypes, but too poorly preserved to assign: UF 15761- 59500 (BTBP?), 55201 (also has similarities with TCE?), 55198 (likely BTBP, but shares a few features with BTY), 55176 (BTY?), 55188 (f, BTBP?); UF 15761N (2012)-57653, 57673 (f, pp), 57672 (f), 57670, 57667, 57663, 57675, 57662 (not BTY).

Morphotype SYM

19032-39008—Lamina marginally attached, notophyllous. Shape elliptic; medial symmetry asymmetrical. Lamina unlobed and untoothed. Neither apex nor base preserved. Primary venation pinnate; secondaries festooned brochidodromous. Secondary spacing irregular, angle similar. Secondaries with decurrent or excurrent attachment. Intersecondaries present, parallel to major secondaries, length ~slightly less than subjacent secondary, distal course of intersecondary perpendicular to subjacent major secondary, intersecondaries ~1 per intercostal area (features of intersecondaries hard to determine because the venation is so irregular). Tertiaries and higher order venation irregular reticulate. Freely ending veinlets visible; areolation present.

19032-39014—Microphyllous lamina with marginal attachment. Lamina elliptic to obovate in shape. Medial symmetry very asymmetrical; base not completely preserved. Lamina unlobed and untoothed. Apex acute and straight on one side and acuminate on the other. Base acute and cuneate. Primary venation pinnate (~1 mm wide); agrophics absent. Secondaries festooned brochidodromous; irregularly spaced, angle of divergence from the midvein similar. Secondaries with excurrent attachment to midvein. Intersecondaries present; ~parallel to major secondaries, distal course ~perpendicular to subjacent secondary, frequency ~less than one per intercostal area. Tertiaries irregular reticulate. Higher order venation also ~irregular reticulate, not clearly preserved.

Untoothed: Not assigned to morphotype (NATM)

543

15761-31011—Margin unclear, likely untoothed. Odd pinnately compound leaf. Lateral leaflets with sessile attachment. Leaflets sub-opposite or oppositely attached. Leaflets marginally attached and microphyllous. Length of most complete leaflet 3.8 cm; width 1.1 cm. Leaflet shape elliptic. Leaves appear to be medially symmetrical, but have some base asymmetry. Leaflets unlobed. Primary venation pinnate; no other venation characters preserved.

15761-55178—Marginally attached, microphyllous lamina. Incomplete length 4.7 cm; width ~2 cm. Shape elliptic; leaf appears symmetrical, but incomplete. Unlobed, untoothed leaf with likely acute apex. Base acute and straight. Primary venation pinnate; agrophic veins absent. Major secondaries interaction with the margin obscured (likely brochidodromous), but some appear to fork prior to edge of margin. Secondaries widely spaced, semi-regular at a uniform angle (just shy of 90°) with excurrent attachment. Intersecondaries present, generally perpendicular to midvein. Length variable; distal course not well-preserved; often more than one per intercostal area. Higher order venation not well-preserved.

15761N-43944 (11)—Poorly preserved fragment. Thick primary; irregularly spaced secondaries with excurrent attachment to them midvein. Brochidodromous secondaries, reticulate higher order venation. Intersecondaries present. Remarks—This specimen is too poorly preserved to assign to a morphotype, but it has similarities to BTBP.

15761N-43991—Primary venation pinnate. Lowest secondaries diverge at a broader angle than in rest of lamina. Secondaries regularly spaced. No higher order venation detail preserved including how secondaries interact with the margin. Remarks—This specimen is fragmentary and poorly preserved. It has similarities with the BT morphotypes.

15761N-43994 (50)—Slightly squished leaf, appears mashed with other plant matter. Apex missing. Base acute, convex one side, slightly concave other side. Pinnate primary venation. Higher order venation not preserved.

15761N-57142—Untoothed lamina with pinnate primary venation. Secondaries likely brochidodromous with excurrent attachment. Possible intersecondary. Tertiaries mixed percurrent; fourth order venation reticulate. Likely freely ending veinlets. No apex or base preserved.

15761N-57626—Both base and apex incomplete. Lamina untoothed. Primary venation pinnate. Secondaries regularly spaced and angled. Other details of the venation not preserved. Remarks—This leaf shares features with the TCE morphotype, but could not be assigned due to the lack of detail preserved.

15761N-57627—Lamina petiolate with marginal attachment; preserved petiole ~1.3 mm wide and ~1.2 cm long. Base asymmetrical and semi-rounded. Remarks—Preservation is poor. Possible Cedrela-like, but not much detail is preserved.

544

15761N-57637—Neither base nor apex preserved. Lamina untoothed. Primary venation pinnate; primary ~1 mm wide. Secondaries brochidodromous; regularly spaced with a uniform angle to the midvein and excurrent attachment. Possible intersecondary (more likely a tertiary); the proximal course neither parallel or perpendicular. Tertiaries mixed percurrent to reticulate. Exterior tertiaries looped. Higher order venation appears reticulate. Remarks—This specimen could be a well-preserved example of one of the Cedrela (VCT or TCE) morphotypes, but the lack of an apex or base precludes a morphotype assignment.

15761N-57644—Apex acute; ~straight. Base and most of leaf not preserved. Pinnate primary venation, arching secondaries. Nub-like teeth with a rounded tooth apex; 1-3 teeth per centimeter.

15761N-61487 (maybe census 100)—Neither apex nor base preserved. Margin damaged on left side, possible tooth present on the right side. Venation pinnate. Secondaries regular with excurrent attachment to the midvein—craspedodromous/semicraspedodromous to eucamptodromous. Higher order venation not preserved. Remarks—This specimen has similarities to the VCT morphotype, but could not be confidently assigned due to the limited preservation.

15761N-61499 (141)—Fragment of one of the BT “types” on the front of the hand sample; hand sample has a specimen of morphotype GBT on the back. Not enough detail to determine sub- morphotype of BT.

15761S-57874 (smallest, lightest colored leaf on the hand sample)—Base absent. Leaf untoothed and nanophyllous to microphyllous. Primary venation likely pinnate with slightly irregular brochidodromous secondaries. Intersecondaries present; they are >50% of the subjacent secondary. Intersecondaries reticulate to ramifying and sometimes contact the loop of the major secondaries. Marginal tertiaries looped; other tertiaries poorly preserved, but appear reticulate. Higher order venation not preserved.

18288-58199—Marginally attached microphyllous lamina, 3.3 cm long by 0.8 cm wide and very slightly ovate in shape. Medially symmetrical; base appears asymmetrical. Lamina unlobed and untoothed. Both apex and base acute and convex. Venation pinnate; secondaries and higher order veins not preserved.

19225-51973—Lamina notophyllous, elliptic in shape. Symmetry cannot be determined; apex and base not preserved. Unlobed, untoothed lamina. Primary venation pinnate. Secondaries ~festooned brochidodromous. Possible, discontinuous marginal secondary or fimbrial vein. Secondaries slightly irregularly spaced; generally uniform secondary angle to midvein with decurrent attachment. Intersecondaries present; vary from parallel to major secondaries to closer to perpendicular to midvein. Length of intersecondaries less than 50% of subjacent secondary; distal course generally perpendicular to a subjacent major secondary; frequency usually one per intercostal area. Tertiaries mixed percurrent; epimedial tertiaries basiflexed. Exterior tertiaries looped. Quaternaries and quinternaries irregular reticulate. Areolation present, good development. Freely ending veinlets present with two or more branches, likely dichotomous.

545

Remarks—This specimen has similarities to the VCT morphotype, but it could not be confidently assigned. The intersecondaries look similar. However, this specimen seemed different (from VCT) because of the decurrent attachment of the secondaries to the midvein as opposed to excurrent in the VCT morphotype. The secondaries have a similar decurrent attachment to the midvein in the 15761N-57626 specimen, but the preservation otherwise is very poor. Both this specimen and 15761N-57626 are missing a base and an apex.

19225-52037—Lamina appears entire, but margin wavy. Marginally attached, microphyllous lamina. Stout petiole present, ~1.7 mm wide. Length 3 cm; width 2 cm. Shape ~elliptic. Medially symmetric; base insertion slightly asymmetrical. Lamina unlobed, likely untoothed (or possible tiny tooth nubs). Apex obtuse, convex. Base obtuse, convex. Primary venation pinnate; possible naked basal vein. Agrophics absent; secondaries ~brochidodromous. Secondary spacing decreases proximally; angle uniform in lower half of leaf, upper half of leaf hard to determine (few clear secondaries preserved). Secondaries with excurrent attachment to the midvein. Tertiaries mixed percurrent; higher order venation not preserved.

19225-54579—Marginally attached lamina, notophyllous. Shape ~elliptic, but upper half of leaf not preserved. Medial symmetry could not be determined; base asymmetrical both in width and insertion. Unlobed leaf (margin likely untoothed, but the preservation poor and has teeth-like projections on one side, but it may just be damaged). Apex missing. Base obtuse; shape concavo- convex on one side, other side convex. Primary venation pinnate; one basal vein present. Secondary type not clear. Perimarginal veins present – marginal secondary to fimbrial vein. Secondaries widely spaced; basal secondaries more acute than others. Some secondaries decurrent. Intersecondaries perpendicular to midvein in some cases, or slightly more acute. Intersecondaries or possibly tertiaries (preservation poor) variable in length; more than one per intercostal area (this provides support for them being tertiaries). Higher order venation not preserved. Remarks—This leaf has similarities to a morphotype preserved in the upper horizon.

19225-54609—Leaf appears ~compound; other details not well-preserved. Marginally attached leaflets? microphyllous. Length 4 cm; width 8 mm. Shape elliptic. Medially symmetrical, base appears asymmetrical (insertion?), but details obscured. Unlobed, untoothed leaf. Apex acute, straight to slightly convex; base acute, straight to slightly convex. Primary venation pinnate; secondaries interaction with the margin is not visible. Secondaries irregularly spaced and have a variable angle to the midvein. Secondary attachment frequently decurrent. Intersecondaries not obvious although some well-defined epimedial tertiaries could be intersecondaries. Tertiaries irregular, although many run in a course perpendicular to the midvein toward the margin. Higher order venation not preserved.

19225-57031—Microphyllous, untoothed leaf fragment. Apex acute and straight. Primary venation pinnate; major secondaries brochidodromous. Areolation present, good development. Freely ending veinlets present with two or more branches.

Part III: Dicotyledonous Leaf Morphotypes from the Upper Horizon

Morphotype—DE

546

19297-43787 (51)—Marginally attached petiolate lamina, notophyllous. Lamina appears symmetrical, but apex missing. Lamina unlobed and toothed (serrate). Apex missing; base acute and straight. Venation pinnate. Marginal vein present. Secondaries travel along margin for a bit and appear semicraspedodromous. Tertiaries appear percurrent, but very faint. Higher order venation not preserved. Three to four teeth per centimeter. Sinuses angular; tooth shape ST/ST.

19297-54303 (?, f)—Marginally attached, microphyllous lamina. Shape elliptic. Lamina medially symmetric, base slightly width asymmetrical. Unlobed lamina, with what looks like small teeth. Apex not preserved; base acute and straight. Primary venation pinnate with one basal vein. Secondaries semicraspedodromous. Intersecondary visible, irregular course (perpendicular to midvein), more than half of length of subjacent secondary. Tertiaries mixed percurrent. Higher order venation not well-preserved, but ~irregular reticulate. One order of small, appressed teeth present.

Morphotype—MAC

19297-43665 (32)—Secondaries semicraspedodromous; some intersecondaries bend down and meet the subjacent secondary perpendicular. One lobe over 13 cm long (that is all that is preserved).

19297-43734 (76)—Marginal secondary present. Intersecondaries visible, as described in specimen 19297-43761. Teeth less hook like than some other specimens of this morphotype.

19297-43737—Hole feeding present.

19797-43750—No margin preserved, but venation matches the MAC morphotype. Tertiaries mixed percurrent. Higher order venation regular reticulate.

19297-43761 (116)—Intersecondaries present, perpendicular to midvein at junction with midvein and then parallel to major secondaries. Intersecondaries more than 50% of subjacent secondary in length, distal course appears to bend and contact the apical secondary, meeting it almost perpendicular. Less than one intersecondary per intercostal area. Higher order venation regular reticulate. Teeth the same as described in 19297-43767. This specimen has insect damage, likely hole feeding.

19297-43767 (185)—Teeth very hook-like, 2-3 per centimeter. Sinuses rounded; tooth shape CC/CV to CC/ST to CC/RT.

19297-43782 (210)—Specimen likely 5 lobed, at least macrophyllous, but incomplete. The venation is not well-preserved.

19297-58165 (98, ?, f)—Fragment, no apex or base. Closely spaced semicraspedodromous secondaries with regular spacing and uniform angle and excurrent attachment. Tertiaries mixed percurrent. Quaternaries and quinternaries irregular reticulate. Areolation present with good development. Teeth with slightly irregular spacing. Two orders of teeth; two per centimeter.

547

Sinuses rounded. Tooth shape varies from CC/CV to ST/ST. Principle vein present; termination partially obscured, but appears to be slightly on the distal flank.

Morphotype—PL

19297-54232 (?, f)—Base, apex, and right side missing. Lamina toothed (serrate). Secondaries semicraspedodromous with lots of branching. Tertiaries ~mixed percurrent. Fimbrial vein present. Teeth regularly spaced; ~3 teeth per centimeter. One order of teeth visible; sinuses rounded. Tooth shape ~CC/ST. Principle vein present, terminates at the apex of the tooth.

19297-58120 (?46?)—Marginally attached leaf notophyllous. Symmetry and shape cannot be determined. Base distorted; apex missing. Visible portion of lamina unlobed and toothed. Primary venation pinnate. Agrophics present; simple where visible. Secondaries semicraspedodromous. Secondary spacing somewhat irregular; angle abruptly increasing proximally. Secondaries with excurrent attachment to midvein. Intersecondaries present, intermediate between parallel to major secondaries and perpendicular to midvein. Intersecondaries less than 50% of subjacent secondary. Intersecondary distal course ~perpendicular to subjacent major secondary. Less than one intersecondary per intercostal area. Tertiaries mixed percurrent. Epimedial tertiaries mixed percurrent, more opposite. Higher order venation not preserved. Teeth present, not well-preserved.

19297-58126 (39, p)—Marginally attached petiolate leaf, notophyllous. Petiole just over 1 mm wide and ~12 mm long. Lamina 6 cm long by ~4 cm wide. Shape ovate. Medial symmetry cannot be determined. Base may have slight insertion asymmetry. Lamina unlobed and toothed. Apex acute, likely straight. Base obtuse, slightly concavo-convex. Primary venation pinnate. One basal vein; agrophics present. Secondaries semicraspedodromous to craspedodromous. Marginal secondary present. Major secondary spacing decreases proximally with a corresponding secondary angle abruptly increasing proximally. Secondaries with excurrent attachment to the midvein. Intersecondaries present, intermediate between parallel to major secondaries and perpendicular to midvein. Intersecondary less than 50% of subjacent secondary; distal course perpendicular to a subjacent major secondary. Intersecondary frequency less than one per intercostal area. Tertiaries mixed percurrent where visible. Higher order venation not preserved. One order of regularly spaced teeth. Sinuses rounded. Teeth CC/ST in shape. Principle vein present; terminates at the apex of the tooth.

Morphotype—CN

19297-43756 (f)—Tertiaries mixed percurrent, more opposite than alternate. Higher order venation present, but faint.

19297-43781 (181)—Microphyllous leaf fragment is elliptic in shape. Medially symmetric; base missing. Apex acute and straight. Primary venation pinnate; secondaries craspedodromous with very regular spacing and angles with excurrent attachment. Higher order venation not preserved. One order of regularly spaced teeth with angular sinuses. Three to four teeth per centimeter. Tooth shape is ST/ST; principle vein present; terminates at the tooth apex.

548

19297-43898 (17)—Base acute, straight; no apex preserved. Higher order venation irregular reticulate with freely ending veinlets present.

Morphotype—RN

19297-58136 (53, ?, p)—Marginally attached lamina, notophyllous. Incomplete length is 7.5 cm, width 2.2 cm. Shape likely ovate, but apex not preserved. Medially asymmetric; basal insertion asymmetrical. Lamina unlobed and toothed (serrate). Base acute and cuneate. Primary venation pinnate; secondaries semicraspedodromous or craspedodromous. Higher order venation not preserved. Tooth spacing slightly irregular with one order of teeth. Two to three teeth present per centimeter with strong angular sinuses. Tooth shape ST/ST to ST/CV. Principle vein present. Remarks—Although the venation on this specimen is poor, it looks like some of the examples of Rhus nigricans (Lesquereux) Knowlton from the Green River Formation (MacGinitie, 1969).

Morphotype—CS

19297-43672 (50, pp)—Microphyllous fragment. Secondaries bend about halfway along their course toward the apex and travel for a bit along the margin. Intersecondaries present, parallel to a major secondary until it meets it. No apex or base, but likely acute and straight.

19297-43674 (29, pp)—Microphyllous lamina, shape linear. Base and apex missing. Venation pinnate. Secondaries appear semicraspedodromous. Higher order venation irregular, but specific pattern unclear. Tooth characters the same as others of this morphotype with a dark bit of tissue on the tip of each tooth apex.

19297-43758 (124, pp)—Lamina microphyllous, incomplete. No apex or base, but likely acute and straight. Secondaries bend about halfway along their course toward the apex and travel for a bit along the margin. Intersecondaries present, parallel to a major secondary until meeting it.

19297-43772 (209, pp)—Marginally attached microphyllous leaf fragment. Shape appears linear to elliptic. Lamina unlobed and toothed (serrate) with slight width asymmetry. Base acute and straight; apex missing. Venation pinnate; secondaries bend up sharply toward the apex, but their interaction with the margin not well-preserved. Patterns of higher order venation could not be determined. One order of regularly spaced teeth with 6 to 7 teeth per centimeter. Teeth have rounded apices and the shape varies from CV/CV to ST/CV to CV/ST. Sinuses angular.

19297-43895 (pp)—Microphyllous fragment, full lamina likely notophyllous. Shape appears to be linear, but much of the leaf missing; width is ~1.2 cm. Lamina medially symmetric, base and apex missing. Venation pinnate. Secondaries appear semicraspedodromous, but very faintly preserved. Higher order venation not preserved. One order of regularly spaced teeth with 5 to 6 teeth per centimeter. Teeth appressed and small with angular sinuses. Teeth CV/CV to CV/ST to ST/CV in shape with rounded apices and longer proximal flanks than distal flanks.

549

Morphotype—“Punctate surface”

19296-43829—Microphyllous lamina, base incomplete, but appears asymmetrical. Stout pinnate midvein. Secondaries craspedodromous to semicraspedodromous (but very faint), secondaries slightly irregular in spacing and angle (60-70°). Secondaries with excurrent attachment. Marginal vein present. Teeth present, ~4 per centimeter. Sinuses angular to rounded. Teeth ST/ST to CV/CV (subtly curved) with rounded apices. Principle vein present with marginal termination; darker pigmented gland present at tooth apex.

19297-43713 (208, ?, pp)—Marginally attached microphyllous lamina. Incomplete length 2.1 cm, width 1.1 cm for a length to width ratio of 1.9:1. Laminar shape elliptic. Medially and basally asymmetrical in width. Lamina unlobed, toothed (serrate). Apex acute, straight to slightly convex. Base acute, straight to slightly convex. Venation pinnate, secondaries likely semicraspedodromous, but very poorly preserved. Secondaries regularly spaced and angled with excurrent attachment. Higher order venation not preserved. One order of regularly spaced teeth, approximately 4 teeth per centimeter. Sinuses angular, tooth shape ST/ST.

19297-43762 (?)—Notophyllous leaf fragment with no apex or base. Medially asymmetric in width. Lamina unlobed, toothed (serrate). Venation pinnate; secondaries semicraspedodromous. Possible marginal vein. Secondaries regularly spaced and angled (60-70°) with excurrent attachment. Possible intersecondary—perpendicular to midvein with a perpendicular distal course. Tertiaries percurrent. Higher order venation not preserved. Two regularly spaced teeth per centimeter. One order of teeth with rounded to angular sinuses. Tooth shape CV/CV to CC/CV to ST/ST. Principle vein present.

19405-61641—Fragment, no apex or base preserved. Venation pinnate, secondaries semicraspedodromous, generally regularly spaced and angled (only small part of leaf preserved). Secondaries diverge at 60 to 70° with excurrent attachment to the midvein. Fimbrial vein present. No higher order venation preserved. Lamina covered with surficial glands. Teeth present, 3-4 per centimeter. Principle vein present with marginal termination. Tooth shape ST/ST to slightly CV/CV (each flank slightly convex).

Toothed: Not assigned to morphotype (NATM)

19296-43802 (28) —Partial lamina, microphyllous. Venation pinnate. Secondaries diverge from midvein at close to 90°, some with decurrent attachment. Teeth with pointed apices, ST/ST in shape. Apex might be untoothed, with secondaries possibly transitioning to brochidodromous. Remarks—This specimen is similar, but not quite the same as morphotype “Punctate surface.” The laminar surface is textured, but does not have the distinctive dot-like glands. Furthermore, the secondaries diverge at much broader angles from the midvein in this specimen as compared to morphotype “Punctate surface.”

19297-43694 (199, f)—Notophyllous, unlobed and toothed (serrate) lamina. Apex and base missing. Primary venation pinnate; secondaries possibly semicraspedodromous, but poorly preserved. Teeth appear regularly spaced with three teeth per centimeter. Sinuses angular. Tooth shape CV/CV to ST/CV.

550

19297-43741 (94, f)—Microphyllous leaf fragment with no apex or base. Venation pinnate. Secondaries appear semicraspedodromous, but little margin is preserved. Intersecondaries present, irregular. Higher order venation not well-preserved. Teeth irregularly spaced with angular sinuses. Principle vein present.

19297-43799 (149, f)—Notophyllous fragment. Shape possibly oblong. Lamina unlobed and toothed (serrate). Apex missing, base incomplete, but appears obtuse and convex. Primary venation pinnate; secondaries semicraspedodromous. Higher order venation not preserved. Only a few poorly preserved teeth present. Some hole feeding observed.

19297-43783 (191, pp)—Notophyllous lamina ovate to linear in shape. Lamina medially symmetric; base slightly asymmetrical in width. Lamina unlobed and toothed (serrate). Apex and base acute and straight. Venation pinnate. Higher order venation not well-preserved. Teeth scattered and widely spaced. Sinuses angular. Tooth shape ST/ST.

19297-43908 (3)—Lamina at least microphyllous. Shape elliptic. Medially symmetric, base missing. Lamina unlobed and toothed (serrate). Apex acute and likely straight, but not completely intact. Venation pinnate, secondaries appear semicraspedodromous. Higher order venation not preserved. Teeth ST/ST to ST/CV with angular sinuses. Principle vein present with termination at the tooth apex.

19297-54204 (darker leaf)—Marginally attached lamina, notophyllous. Incomplete length is 8.1 cm; width at least 1.6 cm. Shape likely elliptic. Symmetry could not confidently be determined, but the base appears asymmetrical. Lamina unlobed and toothed. Apex and base both acute. Primary venation pinnate. Secondaries only faintly preserved. Higher order venation not visible. One order of irregularly spaced teeth. Two to three teeth preserved per centimeter. Sinuses angular. Tooth shape CV/CV to ST/ST with a rounded apex. Remarks—The teeth on this specimen have similarities to the MLA morphotype, but the lack of venation characters precludes a morphotype assignment.

19297-54229—Acute apex, straight (is this the whole leaf or a lobe?); base absent. Craspedodromous to semicraspedodromous secondaries. No higher order venation preserved. Teeth irregularly spaced; two orders of teeth. Three to five teeth per centimeter; angular sinuses. Tooth shape ~ST/CV. Principle vein present, terminates ~between apex of tooth and the proximal flank. Remarks—This specimen may be representative of a new morphotype, but additional, more complete specimens with better venation would be necessary.

19297-54304—Marginally attached lamina, microphyllous. Shape ovate; symmetry cannot be determined. Unlobed, toothed (serrate). Apex not preserved. Base reflex, ~cordate. Primary venation pinnate. Other venation only faintly preserved. Teeth irregularly spaced; one order visible. Two to five teeth per centimeter. Teeth small and appressed; tooth shape ~CV/CV. Remarks—This specimen may be representative of a new morphotype, but additional, more complete specimens with better venation would be necessary.

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19297-54346 (pp)—Marginally attached lamina, notophyllous. Shape ~elliptic; medially and basally ~symmetrical. Unlobed, toothed (crenate). Base acute, shape unclear (straight to convex); apex missing. Primary venation pinnate (primary is 1.5 mm wide near base). Other vein characters not clear; intersecondary visible. Teeth regularly spaced; 4-5 teeth per centimeter. One order of teeth with angular sinuses. Tooth shape CV/CV. Remarks—Although this specimen is too poorly preserved to confidently assign to a morphotype, it is most similar to DE.

19297-58107 (89, pp)—Marginally attached lamina, microphyllous. Length ~5cm, width 1.7 cm for a length to width ratio of ~2.9:1. Shape elliptic. Medially just slightly asymmetric; base not completely preserved. Lamina unlobed, toothed (serrate). Apex acute, straight; base is acute and straight. Primary venation pinnate. Secondaries semicraspedodromous? Secondaries with excurrent attachment to the midvein—appear irregular in spacing and angle, but not all preserved. Higher order venation not well-preserved. Some tooth characters hard to determine. Sinuses angular. Tooth shape ST/CV to CV/CV. Remarks—This poorly preserved lamina may represent a terminal leaflet of morphotype DE, but it is too poorly preserved to assign. The preservation suggests the original lamina was quite thin meaning this leaf could be from an herbaceous taxon, but that is just speculation.

19297-58135—Marginally attached microphyllous lamina. Preserved length is 2.3 cm; width 1.3 cm. Primary venation pinnate. Secondaries possibly craspedodromous. Higher order venation not preserved.

19297-58146 (65, f)—No apex or base. One rounded tooth visible. Central primary vein; veins diverging off midvein ~perpendicular. Remarks—Due to the lack of an apex or base and limited venation characters, this specimen was not assigned to a morphotype. However, the tooth shape and overall size are similar to Serjania rara.

19297-58147 (84)—Wide, pinnate primary ~0.75mm wide. Marginally attached petiolate microphyllous leaf. Base with insertion asymmetry. Medially asymmetrical; teeth only preserved on the wider side. Lamina unlobed, toothed (serrate). Apex not preserved; base acute and straight. Secondaries with excurrent attachment. Teeth ST/CV to CC/CV. Remarks—Although this specimen was not assigned to a morphotype due to the lack of venation characters and an apex, it is most similar to specimens of morphotype RN. However, there are no teeth near the petiole or along the right side, suggesting Rhus is an unlikely assignment.

19297-58151 (77, f, HOV pp)—Fragment lacks an apex and a base. Leaf likely toothed. No venation above secondaries preserved.

19297-58168 (79)—Marginally attached microphyllous leaf fragment. Partial length 2 cm; partial width 1.1 cm. Shape of preserved portion ovate. Symmetry could not be determined. Lamina unlobed and toothed (serrate). Apex acute, straight. Base acute, straight. Primary venation pinnate. Secondaries appear craspedodromous. Secondaries regularly spaced and angled with excurrent attachment. Higher order venation patterns not clearly preserved. Teeth regularly

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spaced with 4-5 teeth per centimeter. One order of teeth with angular sinuses. Tooth shape variable from ST/ST, CV/ST, to CV/CV. Remarks—Although this fragment is too poorly preserved to assign to a morphotype, it is most similar to morphotype CN.

Untoothed

Morphotype—“YAB”

19297-43759 (147, f)—Notophyllous leaf fragment. Shape likely oblong. Lamina unlobed and untoothed. Base and apex missing. Primary venation pinnate; secondaries brochidodromous. Secondaries regularly spaced and angled. Intersecondaries present, almost perpendicular to midvein, less than 50% of subjacent secondary in length, distal course perpendicular to subjacent major secondary, frequency approximately one per intercostal area. Tertiaries opposite percurrent with an obtuse angle to the midvein. Exterior tertiaries looped. Quaternary and quinternary venation irregular reticulate.

19297-54209 (p, ?)—Petiolate lamina, marginally attached and notophyllous. Petiole 1.35 cm long and ~1mm wide near the base of the lamina but swells to >2 mm wide where the petiole would be attached to the branch. Incomplete length is ~11 cm; width 3.7 cm for an approximate length to width ratio of 3:0:1. Laminar shape ovate. Medial symmetry hard to determine due to distortion of the leaf, but may be slightly asymmetrical. Base symmetry cannot be determined because only partially preserved. Lamina unlobed. Margin appears untoothed, but has a lot of damage and unclear undulations. Apex and base angle acute; shape cannot be determined. Venation pinnate; secondaries eucamptodromous to brochidodromous. Perimarginal vein not visible. Secondaries regularly spaced and angled where visible. Secondaries with slightly decurrent to excurrent attachment to the midvein. Intersecondaries present; perpendicular to midvein. Intersecondary length slightly more than 50% the length of subjacent secondary. Distal course perpendicular to subjacent major secondary. Frequency hard to determine due to missing areas, but appears to be less than one per intercostal area. Tertiaries irregular reticulate. Exterior tertiaries looped. Quaternaries and quinternaries irregular reticulate. Areolation with good development. Freely ending veinlets likely present (poorly preserved). Remarks—This specimen has similarities to YAB, but does have a few differences including: no clear marginal vein and a well-defined (relatively short) petiole length. As previously mentioned, the YAB group may represent more than one leaf type, but due to preservational challenges, the leaves were lumped together. This specimen has an uneven/ripped margin, making it challenging to look for a marginal vein. Some specimens placed the YAB group appear to have shorter and/or longer petioles than this specimen. However, the length to width ratio is within the range of the YAB morphotype.

19297-54216 (HOV pp, ?)—Marginally attached lamina, microphyllous. Incomplete length 7 cm; width 1.9 cm. Lamina medially symmetric; base may have some asymmetry, but not completely preserved. Base acute and convex. Apex acute; shape not preserved. Primary venation pinnate. Regularly spaced and angled secondaries (slightly larger angle near base) with excurrent attachment. Higher order venation not preserved. Remarks—This could be a “Cedrela”-like leaflet. Marginal feeding present.

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19297-54231 (f, ?)—Marginally attached leaf fragment, microphyllous. Length, width, shape, and symmetry cannot be determined. Apex and base acute. Base straight to slightly convex where visible. Primary venation pinnate. Secondaries likely brochidodromous, but the margin is only preserved in a few places. Secondaries regularly spaced and angled where visible with a slightly decurrent to excurrent attachment to the midvein. Intersecondaries perpendicular midvein; distal course perpendicular to subjacent major secondary. Much of lamina not preserved, but intersecondary frequency less than one per intercostal area. Tertiaries mixed percurrent to irregular reticulate. Quaternaries and quinternaries irregular reticulate. Areolation with good development. Freely ending veinlets present, mostly with two or more branches.

19297-54301 (p, ?)—Petiolate lamina with marginal attachment. Laminar size microphyllous. Length 5.8 cm; width 1.8 cm for a length to width ratio of 3.2:1. Incomplete petiole 9 mm long by 1.5 mm wide. Shape oblong to slightly obovate. Base appears symmetrical, but slightly distorted. Lamina medially symmetrical, unlobed, and untoothed. Apex acute and likely straight in shape. Base acute and straight to convex. Primary venation pinnate. Secondaries likely brochidodromous (very faint near the margin). Secondaries regularly spaced with secondary angle smoothly increasing proximally. Secondaries with a decurrent to excurrent attachment to the midvein. Tertiaries very faintly preserved in a few spots—mixed percurrent or irregular reticulate. Remarks—Leaf shape and secondaries remind me a bit of TCE from the lower horizon. It is not clear whether or not this specimen has a marginal secondary or intersecondaries—both important characters as to whether it can confidently be placed in the YAB morphotype. However other characters including the length to width ratio match with the YAB morphotype.

19297-54341 (?)—Marginally attached lamina, microphyllous. Slightly incomplete length 7.4 cm; width 2.2 cm. Shape elliptic (close to ovate). Leaf medially symmetric; base incomplete, but appears slightly asymmetrical. Lamina unlobed and untoothed. Apex acute, straight; base acute and ~straight. Primary venation pinnate. Secondaries poorly preserved near margin, ~brochidodromous. Intersecondaries visible. Other venation characters not clearly preserved. Remarks—This specimen is poorly preserved, but does not have a clear marginal vein which is an important character for the YAB morphotype. Also, some of the intersecondaries are longer than 50% of the subjacent major secondary. This specimen has similarities to those from Blue Rim that have been assigned to Cedrela, but the poor preservation precludes a definitive assignment.

19297-54348 (?, HOV pp)—Marginally attached lamina, microphyllous to notophyllous. Length 8.5 cm; width 2.1 cm. Shape ovate (borderline with elliptic). Medially symmetrical where visible. Base insertion asymmetrical. Unlobed, untoothed lamina. Apex acute and likely straight (incomplete); base acute and straight. Primary venation pinnate. Secondaries barely visible. No other higher order venation preserved.

19297-58097 (47, p, ?)—Marginally attached petiolate lamina, notophyllous. Petiole 1.3 mm wide by at least 3 mm long. Incomplete length 7 cm; width 3 cm. Laminar shape oblong or elliptic. Medially and basally symmetric. Lamina unlobed and untoothed. Apex missing; base acute and straight to very slightly convex. Primary venation pinnate. One basal vein. Major

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secondaries brochidodromous with lots of loops up along next apical secondary. Secondaries widely and slightly irregularly spaced. Secondaries with a uniform angle with decurrent to excurrent attachment to the midvein. Intersecondary veins present, parallel to major secondaries. Intersecondary length just slightly over 50% of subjacent secondaries. Intersecondary distal course basiflexed and joining the basal subjacent secondary. Intersecondary frequency usually one per intercostal area. Intercostal tertiaries irregular reticulate to percurrent. Epimedial tertiaries generally opposite percurrent. Exterior tertiaries looped. Quaternaries and quinternaries irregular reticulate. Areolation present with good development. Freely ending veinlets present. Remarks—Marginal insect feeding present.

19297-58098 (73, p, f)—Lower half of petiolate lamina with marginal attachment, microphyllous. Entire lamina may be notophyllous. Base with slight insertion asymmetry, acute, and straight. Preserved petiole 2.7 cm long. Lamina unlobed and untoothed. Primary venation pinnate; secondaries likely brochidodromous, but margin areas poorly preserved. Marginal vein present. Secondaries regularly spaced and angled with excurrent attachment to midvein. Secondaries diverge between 50 and 70°. Higher order venation not preserved. Remarks—Significant marginal feeding present.

19297-58106 (55, ?)—Lower half of lamina only. Marginally attached leaf fragment, microphyllous. Width 3 cm. Lamina medially symmetric; base asymmetrical in width and insertion. Base acute and straight to convex. Lamina unlobed and untoothed. Venation pinnate. Secondaries eucamptodromous to brochidodromous (poorly preserved). Tertiaries mixed percurrent where visible. Higher order venation irregular reticulate where visible. Remarks—Base has some similarities to Cedrela type. It is unclear whether this specimen has a marginal secondary or not and the presence of a marginal secondary is one of the diagnostic characters for the YAB morphotype.

19297-58113 (69, f, ?)—Only central portion of lamina preserved. Margin untoothed. Primary venation pinnate. Secondaries possibly festooned brochidodromous. Tertiaries mixed percurrent where visible. Higher order venation organization not preserved.

19297-58124 (72, HOV pp)—Petiolate lamina with marginal attachment, notophyllous. Shape elliptic to oblong (apex missing). Medially symmetric; basally asymmetric. Lamina unlobed and untoothed. Venation pinnate. Secondaries regularly spaced; secondary angle smoothly increasing proximally. Major secondary attachment to midvein excurrent. Higher order venation not preserved. Some secondaries dichotomously branch in a “Y” shape as they approach the margin.

19297-58125 (HOV pp, ?)—Notophyllous leaf fragment. Untoothed margin. Primary venation pinnate. Secondaries regularly spaced with excurrent attachment. Secondary interaction near margin not preserved, but one secondary forms a “Y” branch. Veins near base with near 90° angle of divergence from midvein transitioning to about 60° in middle of the leaf. No higher order venation preserved. Remarks—The part of this lamina that is preserved looks like specimens from the lower horizon assigned to Cedrela schimperi (morphotype TCE).

555

19297-58158 (HOV pp, ?)—Lower half of marginally attached microphyllous leaf. Width 1.55 cm. Lamina medially symmetric. Base asymmetrical in width (could be preservational). Base acute and straight. Primary venation pinnate. Secondaries faint near margin, possibly eucamptodromous or brochidodromous. Secondaries with regular spacing and angle with excurrent attachment. Intersecondaries not visible. Tertiaries opposite percurrent (only preserved in small area of leaf). Higher order venation alternate percurrent to irregular reticulate.

19297-58187 (f, ?)—Lower half of lamina only. Marginally attached leaf fragment, microphyllous. Width 1.7 cm; medially symmetric. Base appears symmetric. Lamina unlobed and untoothed. Primary venation pinnate. Secondaries faint; likely brochidodromous. Higher order venation not preserved.

Morphotype—“O”

19297-43702—Lamina mesophyllous. Length at least 14 cm, width ~6 cm for a length to width ratio of ~2.3:1. Shape elliptic. Medially symmetric; base missing. Lamina unlobed and untoothed. Apex acute and slightly convex. Venation pinnate. Secondaries brochidodromous. No obvious marginal vein. Major secondary angle to midvein ~uniform, but base missing. Major secondary attachment to midvein excurrent to decurrent. Intersecondaries present; perpendicular to midvein, less than 50% of subjacent secondary, distal course perpendicular to subjacent major secondary. Intersecondaries sometimes with more than one per intercostal area. Tertiaries mixed percurrent. Exterior tertiaries looped. Quaternaries and quinternaries irregular reticulate. Areolation present, good development. Freely ending veinlets present, mostly with two or more branches.

19297-43790 (49, HOV wp)—Lamina petiolate and marginally attached; notophyllous. Length ~8 cm, width ~4 cm for a length to width ratio of 2:1. Shape elliptic. Symmetry could not be determined. Lamina unlobed and untoothed. Apex acute and acuminate. Base acute and cuneate where visible. Venation pinnate. Secondaries brochidodromous; no obvious marginal vein. Secondaries slightly irregularly spaced with slight variations in angle of attachment to the midvein. Secondaries with decurrent to excurrent attachment. Intersecondaries present, irregular, generally parallel to major secondaries. Intersecondaries more or less than 50% of subjacent secondary; distal course perpendicular to subjacent major secondary, occasionally contacting the secondary on the apical side, rather than the basal side. Occasionally more than one intersecondary per intercostal area. Tertiaries mixed percurrent to irregular reticulate. Quaternaries irregular reticulate; quinternaries irregular reticulate. Areolation present; good development. Freely ending veinlets present, mostly with two or more branches, branching appearing dichotomous.

19297-58170 (67, ?)—Incomplete lamina, microphyllous. Incomplete length 3.5 cm; width 1.8 cm. Shape appears to be elliptic. Symmetry could not be determined. Apex acute and acuminate. Lamina unlobed and untoothed. Primary venation pinnate; secondaries likely brochidodromous (also look eucamptodromous in a few places). Intersecondaries not visible. Where preserved, tertiaries irregular and percurrent. Higher order venation irregular reticulate. Freely ending veinlets present.

556

Morphotype—“Loop”

19296-54648 (?)—Marginally attached laminae, notophyllous. Length at least 7 cm, incomplete width ~2.9cm. Shape likely elliptic. Symmetry not preserved. Lamina unlobed and untoothed. Base likely asymmetrical. Apex acute and straight; base obtuse, preserved side is straight. Venation pinnate. Secondaries brochidodromous, loops well-aligned. Fimbrial vein present. Secondaries regularly spaced and angled where visible with excurrent attachment. Secondaries diverge from midvein at 60 to 70°. Tertiaries mixed percurrent. Higher order venation not preserved.

19297-58171 (54, HOV pp)—Marginally attached, microphyllous lamina. Length 6.9 cm, width 1.8 cm. Laminar shape ovate; medial and basal width asymmetry present. Apex acute with a straight to acuminate shape. Base acute and convex and straight in shape. Unlobed, untoothed leaf. Primary venation pinnate; secondaries brochidodromous. Higher order venation not preserved.

Morphotype—“Marquise”

19297-58164 (44, p)—Marginally attached, petiolate, microphyllous lamina. Petiole 3 mm long by ~0.7 mm wide. Lamina 3.2 cm long, width 1.4 cm. Shape oblong. Medially and basally symmetric. Lamina unlobed and untoothed. Apex acute, emarginated in shape. Base acute and straight. Primary venation pinnate. Secondaries regularly spaced and angled, some “V” before looping near margin. Marginal vein present.

Morphotype—“Reverse teardrop”

19297-54215 (p, f, ?, pp)—This leaf looks like it is truly pinnate with a single primary rather than some type of actinodromous (like the other specimens of this morphotype). Secondaries are branching off of the primary and arching toward the apex. Lamina not well-preserved overall.

19297-54338 (pp)—This specimen is similar to 19297-58111, but it looks like there may be 5 rather than three primaries originating at the base of the leaf and traveling toward the apex. Preservation is poor; there may be a branch off the side (middle) primary.

UF 19297-58111 (71, ?, HOV pp)—Marginally attached petiolate lamina, microphyllous. Shape elliptic. Medially very slightly asymmetrical. Base symmetrical. Lamina unlobed and untoothed. Apex not preserved. Base acute, straight in shape. Primary venation basal actinodromous to basal acrodromous. Higher order venation not preserved. Remarks—This specimen has some similarities to morphotype “Reverse teardrop.” However, the lateral primaries are closer to the margin in this specimen and don’t have obvious veins branching off them toward the margin as observed in a lot of the other “Reverse teardrop” specimens.

Morphotype—SYZ: “Syzygioides”

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19297-54326—Marginally attached lamina, microphyllous. Length 3.8 cm, width 1.1 cm. Medially symmetric; base asymmetrical in width and insertion. Leaf unlobed and untoothed. Apex and base both acute and convex to straight. Venation pinnate. Secondaries frequent, thin (narrow gauge), and regularly spaced and angled where visible. Secondaries possibly eucamptodromous or brochidodromous. Higher order venation not preserved.

19297-54335—Microphyllous linear lamina, 5.4 cm long (incomplete) by 7 mm wide. Medially and basally symmetric. Unlobed, untoothed. Base acute and straight; apex not preserved. Primary venation pinnate. Intramarginal secondary present. Regularly spaced and angled excurrent secondaries (or tertiaries??) between primary and intramarginal secondary. Higher order venation not preserved.

19297-58116 (38)—Marginally attached lamina, nanophyllous (apex missing). Incomplete length 2.5 cm; width 6.5 mm. Shape ~oblong. Medially symmetric. Base slightly asymmetrical. Lamina unlobed and untoothed. Primary venation pinnate. Secondaries closely spaced with a regularly spacing and angle where visible. Preserved higher order venation appears irregular reticulate.

19297-58117 (?, p, pp)—Petiolate, marginally attached lamina with an incomplete length of 5 cm; width 1.4 cm. Lamina microphyllous. Shape, based on visible portion, elliptic. Medially and basally symmetric. Lamina unlobed; likely untoothed. Primary venation pinnate. Secondaries faint; regularly spaced and angled where visible. Tertiaries not visible. Higher order venation irregular reticulate where preserved.

19297-58118 (58, ?)—Partial fragment microphyllous. Shape, symmetry, apex, or base characters cannot be determined. Lamina unlobed and untoothed. Primary venation pinnate; secondaries brochidodromous. Possible marginal/intramarginal vein. Secondary spacing regular in middle of leaf, possibly abruptly increasing proximally. Secondaries with one pair of acute basal secondaries. Middle secondaries diverge from primary at ~40°. Secondaries with decurrent to excurrent attachment to the midvein. Intersecondaries may be present; hard to differentiate secondaries and possible intersecondaries. Tertiaries with an irregular course.

19297-58138 (64, ?, HOV pp)—Base of marginally attached leaf fragment, nanophyllous. Width 7.5 mm. Shape likely oblong. Apex missing; base acute and straight to convex. Lamina unlobed and untoothed. Primary venation pinnate. Secondaries regularly spaced and angled where visible.

19297-58167 (57, ?)—Marginally attached lamina, microphyllous. Length and width incomplete. Lamina unlobed, likely untoothed. Primary venation pinnate. Secondaries closely spaced and regularly angled where visible. Secondaries may be brochidodromous.

19297-58169—Marginally attached lamina, nanophyllous. Length 2.4 cm; width 6 mm. Shape just slightly ovate. Medially slightly asymmetrical. Base with width and insertion asymmetry. Lamina unlobed and untoothed. Primary venation pinnate; secondaries closely spaced where preserved and uniform in angle. Higher order venation not preserved.

Morphotype—WSB: “Widely spaced secondaries, balloon”

558

19297-58173 (42, ?, HOV pp)—Two poorly preserved untoothed leaf fragments. Larger specimen notophyllous. Apex and base missing. Laminar shape ovate. Medially symmetric; unlobed and untoothed. Primary venation pinnate; secondaries widely spaced. Secondaries with excurrent attachment to midvein. Higher order venation not preserved.

Untoothed: Not assigned to morphotype (NATM)

19296-43810 (43-45) —Leaf petiolate, palmately or pinnately compound with three leaflets. Leaflets petiolate and marginally attached. Leaflets opposite—odd pinnately compound (if not palmately compound). Leaflets microphyllous. Laminar shape elliptic. Base acute, straight; apex not preserved. Where visible, leaflets with basal insertion asymmetry. Leaflets unlobed and untoothed. Venation pinnate; no other venation characters preserved.

19297-43675 (93, p)—Marginally attached, petiolate fragment. Acute base and apex. Venation pinnate. Secondaries diverge at wide angles from midvein. Higher order venation not preserved.

19297-43701 (165, p)—Marginally attached microphyllous lamina. Shape likely elliptic or oblong, but apex missing. Base asymmetrical in width. Laminar tissue extends down petiole. Leaf unlobed and untoothed (near petiole, margin not preserved once leaf margins are more parallel). Base acute and straight to slightly convex. Primary venation pinnate; secondaries likely brochidodromous, although course near margin not well-preserved. Secondaries regularly spaced and angled with excurrent attachment. Secondaries diverge at ~45-60°. Higher order venation not well-preserved.

19297-43906 (18)—Microphyllous leaf fragment, base missing. Apex acute and straight. Primary venation pinnate. Marginal secondary. Secondaries brochidodromous. Secondaries widely, but consistently spaced where visible. Tertiaries and higher order venation appear irregular reticulate. Freely ending veinlets present.

19297-54204 (lighter leaf)—Marginally attached, notophyllous lamina. Length incomplete; width 4.4 cm. Shape and symmetry could not be determined. Lamina unlobed and untoothed. Primary venation pinnate, primary stout; agrophics absent. Secondaries not well-preserved near margin, but likely brochidodromous. Secondaries with irregular spacing where visible. Major secondaries with excurrent attachment to the primary, but a delta-like swelling of vein tissue visible. Secondaries also fan out into a larger delta of tissue as they approach the leaf margin. Intersecondaries present; perpendicular to the midvein and greater than 50% of the subjacent secondary in length. Intersecondary distal course perpendicular to subjacent major secondary. Tertiaries appear percurrent, although only faintly preserved. Higher order venation appears irregular reticulate, but not well-preserved.

19297-54213—Base of untoothed leaf only. No petiole preserved; likely marginal attachment, although lamina folded near base. Fragment microphyllous. Base acute and convex in shape. Primary venation pinnate. Secondaries ~brochidodromous, but only preserved near margin in one place. Based on preserved portion, there one pair of acute basal secondaries. Secondaries with excurrent attachment to the midvein; diverge at approximately 90°. Intersecondaries

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present; ~perpendicular to midvein although with a course angled toward the base of the leaf. Length and distal course could not be determined; frequency less than one per intercostal area. Tertiaries mixed percurrent; exterior tertiaries looped. Quaternaries and quinternaries irregular reticulate. Areolation present, good development; areoles small in size. Freely ending veinlets not obvious, although preservation may be a factor. Remarks—This specimen may be representative of a new morphotype, but as most of the leaf is missing and it could not be matched to any other specimens it remains NATM.

19297-54217—Lower half of marginally attached leaf preserved. Petiole absent. Preserved portion microphyllous; although it may be a small notophyll. Partial length 6 cm; width 3.35 cm. Lamina symmetrical, unlobed, and untoothed. Apex missing; base slightly obtuse and convex. Base may have insertion asymmetry. Primary venation pinnate. Secondaries brochidodromous to eucamptodromous. Perimarginal vein not present. Secondaries ~regularly spaced with the angle smoothly increasing proximally (the vein angle change is quite subtle). Secondaries with an excurrent attachment to the midvein. Intersecondaries present; perpendicular to midvein and less than 50% of the subjacent secondary in length. Intersecondary distal course perpendicular to a subjacent major secondary (apical direction) with a frequency of less than one per intercostal area. Higher order venation not well-preserved, but appears to be fine and irregular reticulate.

19297-54218—Marginally attached microphyllous lamina (close to nanophyllous). Incomplete length 3.1 cm, width 7.5 mm. Medially symmetric; base appears asymmetrical, but incomplete. Shape is oblong. Lamina unlobed and untoothed. Apex and base acute; shape not preserved. Primary venation pinnate. Higher order venation not preserved. Remarks—This specimen is the shape and size of many of the specimens assigned to the Syzygioides morphotype, but the lack of secondaries or any higher order venation prevents it from being assigned to a morphotype.

19297-54219—Marginally attached lamina, microphyllous. Length 6.3 cm; width 1.4 cm for a length to width ratio of 4.5:1. Shape elliptic. Medially asymmetrical; base symmetrical. Unlobed, untoothed. Apex acute and straight to slightly convex. Base acute and straight. Primary venation pinnate. Secondaries thin and irregular in course. Higher order venation not preserved. Remarks—Although this lamina may be representative of a new morphotype based on the seeming irregularity of the secondaries, the lack of any higher order venation makes it difficult to determine whether this specimen is truly something different or just a poorly preserved example of something already documented.

19297-54224 (pp)—Incomplete length 3.7 cm; width ~7.3 mm. No venation other than primary preserved. Remarks—This specimen is similar to 19297-54218 in that it has similarities to the Syzygioides type, but cannot be assigned due to the lack of any venation.

19297-54227—Partial fragment. Marginally attached lamina; petiole not preserved. Base slightly obtuse and convex in shape. Primary venation pinnate. Secondaries with excurrent attachment diverging at angles around 60-70°. Tertiaries mixed percurrent, mostly opposite with a convex course.

560

19297-54307 (f, pp)—Leaf fragment. Stout primary >1mm wide. Secondaries diverge from midvein between ~60-70 degrees. Secondaries with decurrent and excurrent attachment to midvein. Higher order venation characters not preserved.

19297-54310—Part of upper half of lamina preserved. Likely untoothed margin, but not clear. Secondaries ~brochidodromous. Other venation characters not preserved.

19297-54322—Small fragment with untoothed margin. Intramarginal secondary present. Tertiaries between ~primary and intramarginal secondary opposite percurrent.

19297-54332—Lamina likely microphyllous; only the base preserved. Lamina marginally attached. Base obtuse; straight transitioning to convex. Lamina untoothed where visible. Primary venation pinnate. Secondaries not well-preserved because margin incomplete. Tertiaries ~mixed opposite/alternate. Higher order venation irregular reticulate.

19297-54336 (entire lamina)—Lamina microphyllous. Marginally attached; length incomplete, width ~3 cm. Shape elliptic. Symmetry could not be determined. Leaf unlobed; margin not well- preserved, likely untoothed. Apex not preserved; base obtuse, convex. Venation pinnate; secondaries not well-preserved near margin. Secondary angle smoothly increasing proximally. Higher order venation only preserved in small areas; appears reticulate. Remarks—This specimen has similarities to morphotype TCE from the lower horizon. However, the lack of higher order venation, a complete base, or a complete apex precludes a morphotype assignment. Hole feeding is present.

19297-54342—Poorly preserved fragment; only apex present. Untoothed margin. Apex acute and straight. No venation other than a few brochidodromous secondaries preserved.

19297-54350—Broken fragment (base missing). Untoothed lamina with acute, likely convex apex. Fragment microphyllous. Primary venation pinnate; secondaries likely brochidodromous. Higher order venation not preserved.

19297-58103 (12, HOV pp)—Lamina petiolate, marginally attached, and microphyllous. Petiole ~2.7 cm long. Apex absent; base obtuse, convex. Multiple veins diverge near the base. Possible craspedodromous minor secondaries. Margin unclear, untoothed near base, possibly toothed away from base.

19297-58145 (90)—Apex fragment, microphyllous. Apex acute and straight. Lamina untoothed. Primary venation pinnate; secondaries faintly visible; possibly brochidodromous. Likely intersecondaries. Organization of higher order venation not preserved.

19297-58148 (f, HOV wp)—Fragment, with no apex or base. Untoothed margin. Tertiaries mixed percurrent. Quaternaries and quinternaries irregular reticulate. Areolation present with good development. Freely ending veinlets present with two or more branches where visible. Remarks—Although this fragment has very well-preserved higher order venation, the lack of other characters including an apex, base, or overall shape prevents this lamina from being assigned to a morphotype. The higher order venation has similarities to 19297-43702 & 43790.

561

19297-58153 (p, f)—Partial fragment. Thick primary and margin. No other venation details preserved.

19297-58154 (100)—This specimen has some similarities to 19297-58111, but has a thicker petiole and primary than 19297-58111; sub-primaries are prominent, but not as thick as primary. A few poorly preserved veins present between primaries, running in a somewhat perpendicular course to the primaries.

19297-58166 (70, p)—Marginally attached petiolate lamina, microphyllous. Petiole 1.5 mm wide where preserved. Length 3.6 cm, width 2.4 cm for a L:W ratio of 1.5:1. Shape elliptic. Medially and basally symmetric. Unlobed, untoothed. Apex acute, convex; base just slightly obtuse and straight. Primary venation pinnate. Higher order venation not preserved. Remarks—It is possible the apex of this lamina is emarginate, making it similar to morphotype “Marquise” in that regard. However, the tip of the leaf is damaged, likely by insects, making it challenging to confidently determine the apex shape. The lamina also resembles that of some herbaceous taxa. Overall, this lamina is not well enough preserved, especially since no venation is present, to be recognized as a new morphotype.

19297-58177 (f, HOV wp)—Base only of marginally attached leaf. Base obtuse, convex. Primary venation pinnate. Secondaries brochidodromous. Marginal venation looped. Higher order venation irregular reticulate. Remarks—Although this fragment has higher order venation preserved, there is not enough of the lamina present to assign to a morphotype.

19297-58185 (29)—Marginally attached, notophyllous lamina. Laminar shape elliptic to oblong. Symmetry cannot be determined. Lamina unlobed and untoothed. Apex not preserved; base obtuse and straight to convex. Primary venation pinnate. Secondaries regularly spaced and angled with decurrent to excurrent attachment. Tertiaries percurrent in the limited places they are preserved. Higher order venation not preserved. Remarks—Secondaries very regularly spaced and angled, they seem more so than the YAB morphotype; it is not clear if a marginal vein is present or not.

Margin unclear: Not assigned to morphotype (NATM)

19297-43635—Marginally attached microphyllous fragment with a stout pinnate primary. Secondaries regularly spaced and angled with opposite to subopposite attachment to the primary. Secondaries diverge at ~60°. Tertiaries appear mixed percurrent. Higher order venation irregular reticulate. Freely ending veinlets likely present.

19297-43636 (f)—Small fragment, no margin present. Regular mixed percurrent tertiaries. No other characters preserved.

19297-43697 (158, f)—Margin unclear, wavy. Primary venation pinnate. Secondaries stout, diverging at angles of approximately 65-70° from the midvein. Higher order venation not well- preserved.

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19297-43703 (154, f)—Margin not preserved. Part of the specimen is covered with pigmented dots—possible Aleurites fragment?

19297-54225—Only apex preserved; intact portion notophyllous. Laminar shape not obovate, but otherwise indeterminable. Medially asymmetrical where preserved. Lamina unlobed with likely untoothed margin (some nubs and undulations are unclear). Apex acute and straight to acuminate (bent to the left). Primary venation pinnate; secondaries simple brochidodromous. Interior secondaries and minor secondaries absent on portion of leaf that is preserved. Marginal vein present, close to secondary gauge. Intersecondaries present; more than 50% of subjacent secondary. Intersecondary distal course ~perpendicular to subjacent major secondary. Tertiaries mixed percurrent. Irregular reticulate quaternaries and quinternaries. Areolation present, good development. Freely ending veinlets present with two or more branches.

19297-54298 (f)—Fragment, center of lamina only; apex and base not preserved. Secondaries diverge at broad angles ~70-90 degrees. Intersecondaries present; ~perpendicular to midvein. Tertiaries ~mixed opposite/alternate. Higher order venation irregular reticulate.

19297-54330—Likely one large fragmented leaf, but tricky to tell with the “layered” preservation. If one leaf, size notophyllous. Margin untoothed where visible. Primary venation pinnate. Secondaries regularly spaced and angled in the visible area with excurrent attachment. Higher order venation not clearly preserved. Remarks—Many of the secondaries branch like the “YAB” morphotype so this specimen may be aligned with that, but it is too poorly preserved to assign.

19297-54334—Fragment, margin type unclear. Secondaries ~brochidodromous. Secondaries with decurrent attachment to midvein. Intersecondaries (possibly a tertiary) present; perpendicular to midvein. Distal course of intersecondary basiflexed. Tertiaries likely irregular reticulate, occasionally forming loops off secondary.

19297-54337 (p) —This specimen has some semi-horizontal veins running between the central primary and the sub-marginal primaries. The margin is not well-preserved. Remarks—The lamina has some similarities to 19297-58154. It also has characters in common with Populus cinnamomoides.

19297-58101 (48)—Two overlapping leaves, both notophyllous. Pinnate primary venation; secondaries brochidodromous. Secondaries with excurrent to decurrent attachment to midvein. Intersecondaries present; ~perpendicular to midvein. Intersecondaries more than 50% of subjacent secondary. Intersecondary distal course not well-preserved. Tertiaries opposite percurrent in the limited areas preserved. Higher order venation irregular reticulate where visible. Remarks—One of the leaves has evidence of hole feeding.

19297-58123 (62)—Only center of lamina preserved, no margin present. Higher order venation well-preserved.

563

19297-58156 (f, nm)—Marginally attached microphyllous lamina. Incomplete length 3.5 cm; width 1.7 cm. Primary venation pinnate. Regularly spaced and angled secondaries with excurrent attachment where visible. Tertiaries percurrent. Higher order venation not preserved. Remarks—This specimen was not assigned to a morphotype due to the lack of a margin, apex, and overall poor preservation, but it is most similar to CN.

19297-58157 (p)—Marginally attached, petiolate, notophyllous lamina. Petiole ~1.5 mm wide by 15 mm long with a swollen base where it would attach to a branch. Base slightly convex on the side it is preserved. Primary venation pinnate. Secondary veins closely spaced with higher divergence angles near the base. Secondaries with excurrent attachment. Higher order venation irregular reticulate in small patch where preserved.

19297-58162 (78, p, pp, nm)—Marginally attached, petiolate, microphyllous lamina. Preserved length is 2.5 cm; width 1 cm. Shape likely elliptic. Symmetry could not be determined. Base and apex likely acute. Primary venation pinnate; secondaries somewhat irregular, where visible. Some higher order venation irregular reticulate.

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APPENDIX C INDIVIDUAL REPRODUCTIVE SPECIMEN DESCRIPTIONS

Morphotype—“Poofball”

15761-22580—This specimen is circular in outline and ~3.3 cm in diameter. 15761-22582—This specimen is ~2.4 cm by ~1.7 cm. The individual subunits are striated with the largest being ~5 mm long by ~2 mm wide and oval in shape. 15761-22586—There are multiple specimens on this hand sample. Two are small and fragmented, the third is larger and more compact with a dimension of ~3.8 cm wide. At higher magnification, a dark carbon-like material is visible. The subunits are preserved in many different planes. The largest specimen has a counterpart, which may have a few stamens. 15761-22586 (isolated subunit)—This subunit preserves up to three stamens. The stamens on the left and right are clear, but the central protrusion is less well-preserved and poorly defined. The left stamen preserves a 1.071 mm long filament and a 0.739 by 0.425 mm anther. The right hand stamen that was carefully exposed preserves a 1.611 mm filament and a 0.660 (may be slightly incomplete) by 0.457 mm anther. Although there is not enough preserved/exposed of the central stamen, there is evidence of the filament arising from the subunit and a circular area of dark material is preserved ~1.291 mm above the subunit. All measurements were completed using ImageJ (Rasband, 1997-onwards). 15761-22587—This hand specimen has two examples of the “Poofball” morphotype. The first is very circular with the subunits tightly clustered with little matrix visible in-between. It is ~2 cm in diameter with possible stamens on one edge. The second specimen is more dispersed and partially missing. It is ~4.2 cm wide at the longest preserved point. It may have a few stamens preserved. One of the largest visible subunits is ~5 mm long and just under ~2 mm wide.

Morphotype—“Tiny 5-petal”

15761-22584—At least 6 flowers of the same type are preserved on this hand specimen. The most complete specimen has a partial diameter of ~5 mm (all petals truncated). The five petals are splayed out and not touching each other. Petals have at least 3 “veins,” one in the center of the petal and one on either edge. Petals are attached to a large central “disk” that is ~2 mm in diameter. 15761-22730—This specimen (~7 mm in diameter) preserves a rounded central structure that is large in comparison to the size of the petals. Measured petal 0.270 cm long, but it depends where the “middle” of the flower is distinguished from the petals. This hand section also preserves numerous disarticulated anthers. 15761N-57319—Cluster of stamens with no clear perianth. Anthers are 1 to 1.5 mm long and ~0.5 mm wide. 15761N-57754—Side view with pedicel (~2 mm) of 5 part tiny flower with stamens. Anthers over 1 mm long.

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15761N-61443—“Tiny 5 petal” flower with large central circular structure (~1.7 mm in diameter), unattached stamens present. 15761S-57931—Five petals, each ~2.5 mm long attached to a large central structure with thickened rim; 3-4 stamens with filaments are visible. Specimen is well-preserved.

Morphotype—“Cup-like flower with tiny stamens”

19337- 61553—Side view of pedicellate flower. Pedicel at least 4.5 mm long. Flower is ~7 mm wide, broad cup shaped with lots of tiny stamens; ~30 anthers visible.

Morphotype—“Petals with central vein”

15761-22731—This specimen is ~10 mm in diameter with six striated petals. The longest preserved petal is 0.546 cm long and 0.248 cm wide. 15761N-57127 (?)—Side view of pedicellate flower. Pedicel almost 6 mm long. Petal ~4 mm long. There appears to be 5 petals, possibly with central vein attached to a central area. This specimen is slightly hard to distinguish from “tiny 5 petal.” 15761N-57298—Flower preserved in side view with ~6 mm long pedicel. Pedicel has prominent central vascular strand. Petals with central vein and parallel lateral veins of a slightly narrower gauge. Parts of 5 petals visible. Likely a few tiny stamens present. 15761N-57330 (?)—Flower with possibly 6 petals; maybe an anther. Not well-preserved. 15761N-57332—Flower with 5 partial petals visible. Petals with central vein. Petal ~5 x 2 mm in size. A few small stamens visible. 15761N-57333—Radially symmetric flower with 6 petals. Petals ~3.5 to 4.5 mm long. Petals attached to central disk which is less than 2 mm in diameter. 15761N-57340—Side view of pedicellate flower. Pedicel over 5 mm long. Petals 5-6 mm long with prominent central vein. Small stamens (sub mm) present, morphology not clear. 15761N-57348 (?)—Three petals visible, one is ~4.5 mm long by ~2.5 mm wide. 15761N-57495—Side view flower with pedicel, preserved portion of pedicel 6 mm long. Petal ~4.3 mm long by ~2.7 mm wide. 15761S-57910—Flower with likely 6 petals, petals have central vein. Complete petal is over 5 mm long. Likely associated anthers nearby, but not attached. 15761S-57911—Likely 6 petal flower, no stamens visible. Well-preserved petal has central vein. 15761S-57932 (?)—Looks like a large version of “tiny 5 petal”; central disk ~2 mm in diameter; petals truncated, but flower >7 mm in diameter, no stamens preserved so hard to confirm morphotype placement. 19225-52014 (?)—Compressed flower, likely 5 petals. Prominent vein down center of petal, lateral veins as well. Intact petal is ~5 by ~2 mm. 19225-54573—Side view of flower with at least 4 petals; no obvious stamens present. Short pedicel preserved, just over 2 mm long.

566

19225-57037—Flower with likely 5 petals, central vein; Two clusters of stamens present, anthers relatively small. Pedicel ~5.5 mm long. 19225-57080—Flower with 5 elliptically shaped petals, midvein down center of petal. Petal ~6 by ~2 mm. Small stamens (~0.7 mm long by 0.1/0.2 mm wide). Labeled as Salicaceae flower. 19337-57997—Flower is 8-9 mm in diameter, petals with thickened margin or marginal vein, central vein present; 6 petals total. 19337-57998—Pointed petals with central vein, petals just over 5 mm long. 19337-61549—Three perianth parts visible, with central vein. Petal is ~5.5 mm long. Pedicel at least 5.5 mm long.

Flowers NATM

Specimens—UF 15761-22651, 30932, 30952, 30981, 30982, 30955, 48610; UF 15761N-43979, 57259, 57294, 57303, 57304, 57308, 57315, 57316, 57321, 57505, 57596, 57714, 57724, 57728, 57729, 57750, 57756, 57758, 61391, 61392, 61394, 61450, 61463, 61795; UF 15761S-57866, 57867, 57893, 57914, 57929, 57930; UF 19225-57042, 57044; UF 19225N-61818, 61834; UF 19337-58091, 58093, 61573, 61589.

15761N-43920—Side view of flower with pedicel, 5-6 petals visible. Looks a bit like a “Sunburst” ovary. No stamens visible. 15761N-49319—Cluster of stamen-like structures arising from thick pedicel like structure. 15761N-57753—Flower in side view—possible transition from flower to fruit, possible “Sunburst”? Pedicel is ~6 mm long. Flower is ~5 mm in height. 19337-61526—A few structures that appear to display the transition from flower to fruit. Pedicels preserved, ~7mm long. Gynoecium/young fruit is variable in size with the smallest dimension being about ~4 mm on any of the examples. Two to three remnant styles preserved. Looks closest to Populus sp./Pseudosalix. 19337-61543—Two small pedicellate flower-like structures. Possibly tiny stamens inside one, but no clear morphological characters preserved. Flowers are “closed” with no isolated perianth units. 19337-61564—Closed flower-like structure with long pedicel. No isolated perianth visible. Possible stamens inside, but not clear. 19337-61588—Multiple attached pedicellate flowers. Pedicel on most complete example is 10 mm long before joining the main stem. Entire flower is ~9 mm wide with petals slightly closed in side view and ~9.5 mm tall. At least 5 perianth parts preserved. Remnants of at least 3 flowers preserved. Other than overall shape and size, no defining characters including androecium or gynoecium preserved.

Fruits/Seeds

Morphotype—“Winged Teardrop”

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19225-52021—Seed ~5.5 mm by 4 mm, wing has an irregular margin where preserved, but extends ~3 mm from seed. 19225-57035 (?)—Seed ~3 mm long by 1.75 mm wide. Wing is less than 1 mm in diameter. 19225-57123—Well-preserved, central seed body is teardrop shaped, ~6 x 4 mm. Seed has a thickened rim and a bumpy surface (based on the pitted impression). Wing is pointed at rounded end of teardrop-shaped central seed body, wing extends ~4 mm. 19297-43753—Not as well-preserved as other specimens, but the seed ~6 mm long by ~4 mm wide; surface looks bumpy or textured. No wing present. 19297-43916—Single seed body in center, raindrop shaped with thickened rim. Seed is ~6 mm in length. Wing extends 2-3 mm from seed. 19297-43917—Seed ~6 mm long by ~4.5 mm wide with thickened rim, rim ~0.5 mm wide. No wing present. 19297-58137—Seed is ~6 x 4.5 mm; wing has an irregular margin, but extends 2-3 mm from seed.

Morphotype—cf. Calycites ardtunensis

19296-43856—Shows at least 3 wings but the total number is not clear. The wings arise from the apical rim of the striate body like features of a shuttle cock. Each wing has a midvein and numerous pinnately arising secondary veins that form a reticulum. The fruit body has at least 5 thick vertical grooves on each counterpart impression, indicating about 10 ribs on the original surface of the ovary. 19296-43857—Shows at least 3 wings arising from the elongate striate fruit body, but more may be hidden in sediment of the missing counterpart.

Fruit/Seed-like structures NATM

Specimens—UF 15761-22611, 22653, 22708, 22715, 30961, 56334, 56335; UF 15761N-57326, 61374, 61376, 61385, 61389, 61404; UF 15761S-57819, 57888; UF 18289-56304; UF 19225- 54560, 56933, 56986, 57052; UF 19225N-61801, 61819, 61825, 61832; UF 19337-61559, 61563.

15761-22779—Crescent shaped fruit, ~14 by 3 mm. Possible seed inside. Small legume pod? 15761N-57745—Five pointed structure with hollow center; center area ~2 mm in diameter. 15761N-57191—Winged heart-shaped fruit or seed? 19225-56931—Wide crescent shaped structure, ~5 mm long. 19225-54560—Elliptically shaped structure, at least 1 cm long, ~ 4 mm wide. Dark center, lighter sides, “marginal vein” present. 19225N-57941—Oblong seed or fruit ~6 mm long by ~2.5 mm wide with narrow pointed ends. Central part is darker and may represent seed.

568

19225N-61803—Tiny winged seed like structures, similar to 19225N-61801, ~3 mm by 1 mm. One with cuticle. Possible remnant style present. 19225N-61828—Crescent shaped fruit/seed, ~11 x 3.5 mm, thickened rim, darker center strip present. 19225N-61830—Heart shaped structure with pedicel; looks like a Brassicaceae silique. Size ~4.25 mm wide by ~4.5 mm long. Central suture between 2 halves of heart present. 19225N-61831—Two side by side wide crescent shaped structures, each ~3.5 x 1.5 mm. 19225N-69005—Multi winged fruit-like structure with pedicel. Most complete wing is ~15 mm by 3.5 mm. Likely 3 wings, but only 2 visible. 19296-43887—Irregularly shaped fruit or seed with multiple chambers. “Leathery” surface texture, ~6 mm in diameter. 19296-43818—A few chambers, ~6 mm in diameter. 19296-43817— Specimen ~8.5 x 8 mm, possible Iodes occidentalis fruit. 19337-57987—“Rabbit ears” or just 2 things that deposited that way, winged seeds or fruits, at least 6 mm wide, ~3 mm wide. Darker center, lighter sides, possible marginal vein. 19337-58090—Small rounded seed or fruit, ~3 mm in diameter with 2 notches. 19337-61544—Elliptic structure with slightly pointed ends and darkened center structure. One end missing. Size ~10 x 3 mm. 19337-61546—“Rabbit ears” type, seems incomplete; “ears” ~12 x 3 mm. 19337-61550—Thickened rim and darker center. Incomplete, ~3 mm wide, >1 cm long. 19337-61577—Rounded seed or fruit ~4 mm in diameter. Surface has uneven, occasionally dichotomizing parallel lines that are less than 0.5 mm apart. 19337-61580—Plant part unknown. Curved structure has 2 main veins parallel to each other and an intramarginal vein. In-between the main veins are perpendicular veins, some of which bifurcate. 19404-61724—Large rounded structure ~4.6 cm in diameter. Surface is covered with small concentric circles variable in size (~1.5-3 mm). 19405-61654—“Rabbit ears,” 2 winged fruit? Surface pattern of wings not well-preserved, although darker area in center may represent seed. Wings are ~5 mm in length.

Fruit/Seed Clusters NATM

Specimens—UF 18288-58221; UF 19225N-57938; UF 19232-52315.

15761N-57717—Tiny (sub-mm) rounded seed like structures in cluster (~7 x 4 mm); specific morphology not clear.

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APPENDIX D INDIVIDUAL WOOD SPECIMEN DESCRIPTIONS

Family—Fabaceae Lindl. Subfamily—Caesalpinioideae DC.

Specimen—UF 15761-56323. Description—Diffuse-porous wood with indistinct or absent growth rings. Vessels mostly in short radial multiples. Perforation plates simple; intervessel pits alternate. Mean intervessel pit diameter 6.5 µm (SD = 1.1 µm, Range: 5.0–8.8 µm, n = 10). As most vessels are squished in transverse section, the mean tangential diameter of the vessels and the presence or absence of tyloses could not be determined. Mean vessel element length 173 µm (SD = 40 µm, Range: 130– 261 µm, n = 11). Fiber walls thick to intermediate in thickness. Although the arrangement of parenchyma could not be specifically observed, parenchyma appeared to be present around vessels because it was lighter in color. In addition, there may be some thin bands of parenchyma marking the growth ring boundaries. Rays mostly two-seriate. Rays average 263 µm high (SD = 93 µm, Range: 79–436 µm, n = 30). Ray cellular composition not well-preserved, but rays appear to have procumbent body cells with 1, 2, or 3 upright/square cells. An average of eight rays per millimeter (Range: 6–10, n = 10). No storied structure observed. Occasional small semi- rounded bodies present in ray cells.

Specimen—UF 18591-33042. Description—Growth rings indistinct and weakly defined by bands of marginal parenchyma. Wood likely diffuse-porous. Many solitary vessels, some radial multiples, rare clusters. Solitary vessels rounded, not angular in outline. Perforation plates likely simple. Intervessel pits range from opposite to alternate with more being alternate. Intervessel pit size averages to 5.9 µm (SD = 0.4 µm, Range: 5.0–6.6 µm, n = 10). Mean tangential diameter of vessel lumina 74 µm (SD = 20 µm, Range: 33–108 µm, n = 30). Vessels per square millimeter varies greatly across the transverse section with a range from 0-18 (avg. = 7, n = 12). Paratracheal axial parenchyma present; vasicentric to aliform. Banded parenchyma >3 cells wide and marginal bands present. Rays frequently 1 to 2 cells wide (some may be larger). Some ray cells procumbent; additional details of ray cellular composition not observable. No intercellular canals observed. Semi- rounded structures present in ray cells. Remarks—Two areas of the transverse section have large, wavy tangential lines of dark crushed cells. Right before these rings of crushed cells, the rays appear to fan out. However, no rays appear wider in tangential section and the majority of the transverse section has rays of uniform width. This is likely a preservational distortion. This specimen has many characters in common with specimens UF 19338W-61965 and 19338W-61966 including the arrangement of axial parenchyma and intervessel pit size, but the mean tangential diameter of vessel lumina is much larger on this specimen with fewer vessels per square millimeter. This may be due to plant maturity or the difference between trunk and branch wood.

Specimens—19338W-61965, 61966. Description—Growth ring boundaries indistinct with a diffuse-porous arrangement of vessels. Vessels arranged in a radial pattern, occasional clusters or radial multiples of 4 or more, but more commonly radial multiples of 2 or 3 or solitary vessels. Infrequent, short tangential bands of vessels present. Solitary vessel outline not angular. Perforation plates simple. Intervessel pits 570

alternate with an average diameter of 5.3 µm (SD = 0.3 µm, Range: 4.8–5.8 µm, n = 10, UF 19338W-61965) and 7.1 µm (SD = 0.8 µm, Range: 6.0–8.1 µm, n = 10, UF 19338W-61966). Vestured pits not observed. Vessel-ray pits are small, inconspicuous, and similar to intervessel pits. Helical thickenings not observed. Mean tangential diameter of vessel lumina 49 µm (SD = 19 µm, Range: 21–97 µm, n = 30, UF 19338W-61965) and 45 µm (SD = 17 µm, Range: 13–72 µm, n = 30, UF 19338W-61966). Specimen UF 19338W-61965 has 6 to 20 vessels per mm2 with an average of 14 and specimen UF 19338W-61966 has 6 to 46 vessels per mm2 with an average of 23.3 (both had six areas counted). Mean vessel element length 193 µm (SD = 106 µm, Range: 79–517 µm, n = 24, UF 19338W-61965) and 213 µm (SD = 88 µm, Range: 90–381 µm, n = 30, UF 19338W-61966). Tyloses not observed. Ground tissue pits not observed. Fibers vary from thin to very thick walled. Paratracheal axial parenchyma present with patterns including vasicentric, aliform, occasional lozenge-aliform, and confluent. Occasional marginal parenchyma bands. Axial parenchyma strand length varies from 3 to >8 cells per strand. Ray width mostly 1- 2 cells wide. Average ray height 218 µm (SD = 97 µm, Range: 64–522 µm, n = 30, UF 19338W- 61965) and 189 µm (SD = 77 µm, Range: 90–421 µm, n = 30, UF 19338W-61966). Ray cellular composition variable. Rays homocellular procumbent or with one or two rows of upright and/or square marginal cells. Rays per millimeter averages to 8.6 with a range of 6-12 and 7.8 with a range from 2-12 (specimens UF 19338W-61965 and UF 19338W-61966, respectively). No storied structure or intercellular canals observed. Rare prismatic crystals in chambered axial parenchyma cells. Small, semi-rounded structures present in ray cells. Remarks—Although these two specimens have slight variations, they can be confidently assigned to the same morphotype and may even be from the same tree as they were collected from the same site.

Family—Anacardiaceae R. Br. Genus—Edenoxylon Kruse Species—Edenoxylon parviareolatum Kruse

Assigned (included in morphotype description)

Specimen—UF 00341S-61961. Description—Growth ring boundaries absent with diffuse-porous vessels in a radial pattern. Occasional radial multiples greater than 4, more commonly radial multiples of 2 to 4 or isolated vessels. Solitary vessel outline not angular. Perforation plates simple. Intervessel pits alternate, size averages to 3.8 µm (SD = 0.4 µm, Range: 3.2–4.7, n = 10). Vestured pits, vessel-ray pitting, and helical thickenings not observed. Mean tangential diameter of vessel lumina 48 µm (SD = 13 µm, Range: 19–83, n = 30). Vessel diameter variable, even between adjacent vessels. Vessels per square millimeter ranges from 26 to 44 (mean = 33, n = 6). Mean vessel element length not determined due to the extensive tyloses. Ground tissue fibers not well-preserved; where visible with simple to minutely bordered pits. Helical thickenings in ground tissue fibers not observed. Non-septate fibers present; occasional septate fibers might be present. Fiber walls occasionally very thin-walled, more frequently thin to thick-walled. Axial parenchyma rare; scanty paratracheal and in weak marginal bands. Axial parenchyma with ~3-8 cells per strand (exact cell counts were challenging due to the strands being filled with post-depositional material). Rays mostly 1-2 cells wide; occasionally 3. Aggregate rays absent. Ray height averages to 194 µm (SD = 72 µm, Range: 89–335, n = 30). Ray cellular composition variable ranging from >4

571

rows of upright/square cells to procumbent, square, upright mixed throughout ray (Rays also overlap with each other and the true borders are difficult to determine). Six to twelve rays per millimeter (Mean = 9.4, n = 10). No storied structure observed. Rare radial canals present. Prismatic crystals common in upright ray cells; occasional prismatic crystals in procumbent ray cells. Rarely more than one crystal of the same size per cell. Rare crystals observed in non-ray cells in tangential section, either in axial parenchyma cells or fibers. Remarks—Fibers obscured with post-depositional material, some with horizontal lines that might be true septa.

Specimen—UF 15761-56320. Description—Diffuse-porous wood; growth rings absent (section has areas that are lighter and darker, but these are not clear rings). Vessels mostly aligned with the rays. The longest chains have 5-6 vessels, but most radial multiples are 2, 3, or 4. Solitary vessels also present; outline not angular. Perforation plates simple. Intervessel pits alternate, but not well-preserved. Mean tangential diameter of vessel lumina 61 µm (SD = 13 µm, Range: 44–90 µm, n = 30). Vessel frequency averages to 34 mm2 (Range: 28–44, n = 6). Tyloses common, which obscures the true length of the vessel elements. Fibers with intermediate wall thickness. Arrangement of the axial parenchyma not observed. Rays mostly 1-2 cells wide, rarely 3; wider with radial canals. Rays average 215 µm high (SD = 76 µm, Range: 100–357 µm, n = 30). Ray cellular composition variable. Some rays with procumbent body cells and 1-4 rows of upright square or marginal cells. Other rays with cell types mixed throughout the ray. An average of 19 rays present per millimeter (Range: 10–30, n = 10). No storied structure observed. Radial canals present. A ray with a radial canal measures 390 µm by 60 µm for a length to width ratio of 6.5:1. The canal opening is 72 µm by 31 µm for a length to width ratio of 2.3:1. Prismatic crystals present in upright/square and procumbent ray cells.

Specimen—UF 18289-56305. Description—Diffuse-porous wood with indistinct/absent growth rings. Vessels arranged in radial multiples of 2, 3, 4, >4, or solitary. Perforation plates simple. Vessel-ray pitting oblong rounded or horizontal (gash-like) with much reduced borders to apparently simple. Mean tangential diameter of vessel lumina 58 µm (SD = 15 µm, Range: 14–80 µm, n = 30). An average of 40.3 vessels per square millimeter (Range: 26–54, n = 6). Tyloses common; obscuring vessel element length and intervessel pits. Fibers thin to thick walled. Presence/absence of axial parenchyma could not be determined. Rays mostly 1-2 seriate wide. Rays average 199 µm high (SD = 71 µm, Range: 84–343 µm, n = 30). Rays variable in cellular composition with procumbent body cells and 1-4 square/upright marginal cells or mixed throughout the ray. An average of 18 rays per millimeter (Range: 10–30, n = 10). Storied structure not observed. Radial canals present; one ray measures 712 µm high by 72 µm wide with a canal 121 µm by 61 µm, whereas another ray spans 305 µm in height by 59 µm in width with a canal measuring 63 µm by 39 µm. Prismatic crystals in upright/square and procumbent rays cells average 18 µm (SD = 3 µm, Range: 14–23 µm, n = 7) in longest dimension. No other crystal types observed.

Specimen—UF 18289-56306. Description—Diffuse-porous wood with indistinct growth boundaries. Vessel arrangement solitary or in radial multiples of 2-3. Perforation plates simple; no intervessel pits observed. Mean tangential diameter of vessel lumina 78 µm (SD = 17 µm, Range: 43–113 µm, n = 30).

572

Vessels per square millimeter averages to 14 (Range: 8–22, n = 6). Mean vessel element length 108 µm (SD = 46 µm, Range: 36–195 µm, n = 19). Tyloses present. Septate and non-septate fibers likely present. Fiber walls on the thin side. Axial parenchyma might be present as narrow bands. Rays commonly 1-2 seriate; wider with radial canals. Rays average 186 µm high (SD = 50 µm, Range: 102–303 µm, n = 30). Rays variable in cellular composition with either procumbent body cells and 1-4 rows of upright/square marginal cells or procumbent, square, and upright mixed throughout the ray. Rays per millimeter averages to 16 (Range: 10–20, n = 10). No storied structure observed. Radial canals present. Prismatic crystals present in both upright/square and procumbent ray cells. Remarks—Tyloses and radial canals present, but not as frequent as some of the other Anacardiaceae specimens. The tyloses likely obscured the true end walls of the vessel elements, which may explain why the measurments of vessel element length are so short. Two approaches were used to estimate the specific gravity of this wood specimen. Using the methods of Wheeler et al. (2007a), the specific gravity of this specimen is 0.70, whereas the estimate is 0.96 using equation 1 as supplied by Martínez-Cabrera et al. (2012).

Specimen—UF 18289-56308. Description—Diffuse-porous wood with absent growth rings. Vessels arranged in radial multiples of 2, 3, occasionally 4-5 or solitary. Perforation plates simple. Intervessel pits alternate, but poorly preserved. Mean tangential diameter of vessel lumina 69 µm (SD = 19 µm, Range: 22–101 µm, n = 30). Vessels per millimeter averages to 20 (Range: 12–30, n = 6). Tyloses present, some appear sclerotic. Some fibers septate. Fibers thin to thick-walled. Axial parenchyma characters could not be determined. Rays mostly 1-2 seriate, rarely 3; larger with radial canals. Rays average 167 µm high (SD = 48 µm, Range: 94–293 µm, n = 30). Ray cellular composition variable. Some rays with procumbent body cells and 1-4 rows of upright/square marginal cells or procumbent or square/upright cells mixed throughout the ray. Rays per millimeter averages to 17 (Range: 10–25, n = 10). No storied structure observed. Radial canals present, numerous. Six rays with radial canals average 345 µm (SD = 129 µm, Range: 194–487 µm) high by 62 µm (SD = 9 µm, Range: 46–73 µm) wide. The canals in these rays average 50 µm long (SD = 16 µm, Range: 26–67 µm) by 32 µm wide (SD = 6 µm, Range: 21–37 µm). Prismatic crystals present in both upright/square and procumbent ray cells. No other crystal types observed. Remarks—Some of the rays with canals have super long “tails”, whereas others do not. Preservation is very good. Two approaches were used to estimate the specific gravity of this wood specimen. Specific gravity is estimated to be 0.58 using the methods of Wheeler et al. (2007a), whereas the estimate is 0.82 using equation 1 as supplied by Martínez-Cabrera et al. (2012).

Specimen—UF18591-33008. Description—Growth ring boundaries indistinct. Wood diffuse-porous. Occasional radial multiples of four or more vessels, but more commonly in multiples of 2 or 3 or solidary. Solitary vessels not angular in outline. Perforation plates likely simple. Intervessel pits alternate to occasionally opposite. Helical thickenings not observed. Mean tangential diameter of vessel lumina 54 µm (SD = 16 µm, Range: 26–94 µm, n = 30). Vessels frequency averages to 33 mm2 (Range: 24–40, n = 6). Tyloses present, which obscured vessel element end walls. Fibers thin to thick walled. Axial parenchyma is visible in tangential section, but the pattern cannot be

573

determined in transverse section. Nuclei are visible in axial parenchyma and one strand contained 5 cells. Rays commonly 1 to 2 cells wide; wider with radial canals. Rays average to 253 µm in height (SD = 98 µm, Range: 131–487 µm, n = 30). Rays per millimeter averages to 12 with a range from 6 to 18. No storied structure; radial canals present. Three rays with radial canals vary in size: the first measures 468 µm high by 58 µm wide with a canal opening 37 µm by 23 µm, another ray with a canal is 459 µm high by 82 µm wide with a canal opening 51 µm by 43 µm, and a third measures 393 µm high by 76 µm wide with a canal 81 µm by 50 µm. Prismatic crystals present in upright/square ray cells; one measuring 29 µm in the longest dimension. Remarks—Two approaches were used to estimate the specific gravity of this wood specimen. The specific gravity is 0.73 using the methods of Wheeler et al. (2007a), whereas the estimate is 0.99 using equation 1 as supplied by Martínez-Cabrera et al. (2012).

Specimen—UF 18591-33023. Description—Growth ring boundaries indistinct to absent (preservation is limiting). Wood diffuse-porous with vessels in a radial pattern. Rare radial multiples of four or more, but more commonly solitary vessels or short radial multiples. Solitary vessels not angular in outline. Simple perforation plates. Helical thickenings not observed. Mean tangential diameter of vessel lumina 69 µm (SD = 12 µm, Range: 45–89 µm, n = 20). Vessels per square millimeter averages to ~12 (Range: 10–15, n = 6). Vessel element boundaries obscured by numerous tyloses. Fibers thin to thick walled, occasionally very thick walled. Diffuse apotracheal axial parenchyma present. Rays without radial canals most commonly 1-2 cells wide. Rays average 189 µm in height (SD = 59 µm, Range: 86–364 µm, n = 30). Eight to 16 rays per millimeter with an average of ~12. No storied structure observed; numerous radial canals present (more than other Blue Rim Edenoxylon parviareolatum specimens). Rays with single radial canals average to 494 µm (SD = 114 µm) high by 98 µm (SD = 18 µm) wide (n = 14). The average length to width ratio is 5:1. The canals in those rays average 82 µm long (SD = 15 µm) by 61 µm (SD = 17 µm) with an average ratio of 1.3:1 (n = 14). Occasional rays contained two radial canals; these tended to be slightly shorter than the average of the single canals rays with a lower length to width ratio. Canals generally oblong, but occasionally more rounded in shape. Prismatic crystals present in upright/square ray cells. Remarks—Two approaches were used to estimate the specific gravity of this wood specimen. The estimated specific gravity is 0.83 using the methods of Wheeler et al. (2007a) and 1.35 using equation 1 as supplied by Martínez-Cabrera et al. (2012).

Specimen—UF 18591-33030. Description—Growth ring boundaries indistinct to absent (preservation is limiting). Wood diffuse-porous with vessels arranged in a radial pattern. Vessels solitary or commonly in radial multiples of two, but occasionally with 3 or 4 vessels. Solitary vessels not angular in outline. Simple perforation plates. Intervessel pits alternate averaging to 4.8 µm (SD = 0.7 µm, Range: 4.0–6.6 µm, n = 10). Helical thickenings not observed. Mean tangential diameter of vessel lumina 47 µm (SD = 15 µm, Range: 19–88 µm, n = 30). Six areas were counted to observe vessels per square millimeter resulting in an average of 32 with a range of 24-40. Mean vessel element length not determined because vessels obscured with tyloses. Fibers thin to thick walled, occasionally very thick walled. Rays mostly 1-2 cells wide; rare larger rays (4-10 cells wide). Rays average 206 µm high (SD = 81 µm, Range: 105–478 µm, n = 30). Body ray cells

574

procumbent with likely 1-2 rows of square/upright cells (poorly preserved). Ten to 20 rays per millimeter with an average of 15 (n = 10). No storied structure observed; radial canals present. Rays with single radial canals average 380 µm high (SD = 87 µm) by 60 µm wide (SD = 6 µm) with a length to width ratio of 6:1 (n = 3). The canals average 52 µm long (SD = 9 µm) by 28 µm wide (SD = 4 µm) with an average ratio of 2:1. A ray with two canals measures 499 µm high by 71 µm wide with the larger canal 62 µm by 35 µm and the smaller 35 µm by 21 µm. The smaller canal has a well-defined ring of smaller epithelial cells around the canal. Prismatic crystals present in some procumbent and upright/square ray cells. Crystals average 16 µm in longest dimension (SD = 2 µm, n = 5). Remarks—Two approaches were used to estimate the specific gravity of this wood specimen. Using the methods of Wheeler et al. (2007a) the estimated specific gravity of this specimen is 0.79, whereas it is 0.96 using equation 1 as supplied by Martínez-Cabrera et al. (2012).

Specimen—UF 18591-33021. Description—Growth ring boundaries absent. Diffuse-porous with some solitary vessels and many radial multiples of 2 to 4 vessels. Occasional larger radial multiples. Solitary vessels not angular in outline. Perforation plates likely simple as no scalariform observed. Intervessel pits poorly preserved, likely alternate in arrangement. Intervessel pits minute to small with an average of 4.8 µm (SD = 0.7 µm, Range: 3.3–5.9 µm, n = 10). Average tangential diameter of vessel lumina 60 µm (SD = 23 µm, Range: 19–91 µm, n = 30). Eight to 18 vessels per mm2 with an average of 13 from six counts. Tyloses common. Fibers thin to thick walled. Parenchyma present (observed in tangential section), but arrangement in transverse section not determined due to the inability to distinguish parenchyma and fiber cells. Rays most commonly 2 cells wide; frequently just one cell wide in middle of ray. When single cells present in center of multiseriate ray, width of uniseriate portion equals width of neighboring multiseriate portion. No aggregate rays. Rays average 226 µm in height (SD = 72 µm, Range: 111–383 µm, n = 20). Average of 15 rays per millimeter with a range from 10-20 (n = 10). Ray cellular composition not well- preserved, but usually with procumbent body cells and one to four rows of upright/square marginal cells. Procumbent body cells and one row of upright cells most common. Storied structure not observed. Rare radial canals; one ray with canal measuring 374 µm high by 36 µm wide. Canal opening 40 µm tall by 25 µm wide. Prismatic crystals present in top and middle of rays (as viewed in tangential section). The longest dimension of thirteen prismatic crystals averages to 20 µm (SD = 3 µm, Range: 15–26 µm). Remarks—The two approaches used to estimate the specific gravity of this wood specimen produced divergent results. Estimated specific gravity is 0.87 using the methods of Wheeler et al. (2007a) and 1.22 using equation 1 as supplied by Martínez-Cabrera et al. (2012).

Specimen—UF 18591-33034. Description—Growth rings absent with only slight variations in fiber preservation across the transverse section. Diffuse-porous with vessels solitary or arranged in radial multiples of 2 to 3. Occasional longer radial multiples, rare clusters. Intervessel pits not well-preserved. Mean tangential diameter of vessel lumina 54 µm (SD = 15 µm, Range: 28–96 µm, n = 30). An average of 28 vessels per mm2 (Range: 16–40, n = 6). Vessel elements average to 80 µm long (SD = 31 µm, Range: 30–153 µm, n = 30). Occasional vessels with tyloses. Some fibers very thin walled. Axial parenchyma not distinguishable from fibers in transverse section, but it is visible in longitudinal section. Strands are variable in length with some being four to eight cells

575

per strand (six counted) and others over eight cells (n = 12). Rays one to two cells wide; larger with radial canals. Two individual rays with radial canals measure 389 µm high by 46 µm wide and 363 µm high by 52 µm wide. Prismatic crystals present in ray cells (one measured to 22 µm in longest dimension); possible prismatic crystals in axial parenchyma. Remarks—The measured lengths of the vessel elements are very short. This may be due in part to the presence of tyloses obscuring the true length or mimicking a vessel element end wall.

Specimen—UF 18591-33041. Description—Growth rings indistinct to absent (transverse section poorly preserved) with a high percentage of solitary vessels. No evidence for scalariform perforation plates; therefore likely simple. Tyloses present. Fibers thin to thick walled. Rays 1-3 cells wide, with the majority of rays being 2 cells wide. Rare radial canals present. Prismatic crystals present in ray cells. cf. Anacardiaceae, Edenoxylon parviareolatum (not included in morphotype description)

Specimen—UF 15761-56322. Description—Transverse section poorly preserved, but visible vessels solitary or in short radial multiples. Perforation plates likely simple. Intervessel pits alternate, rounded in outline averaging to 6.3 µm (SD = 0.6 µm, Range: 5.4–7.5 µm, n = 10). Vessel-ray pitting present, but border type (distinct or reduced) could not be determined. Mean vessel element length 149 µm (SD = 51 µm, Range: 73–240 µm, n = 12). Fibers appear numerous, but specific details not preserved. Axial parenchyma present around vessels and scattered based on the presence of vertical strands of square or elongate cells with cell contents. Specific arrangement could not be determined due to the poor preservation of the transverse section. Rays 1-3 cells wide, many with 2 to 4 rows of upright or square marginal cells. Rays average 220 µm in height (SD = 97 µm, Range: 72–415 µm, n = 30). An average of 12 rays per millimeter (Range: 8–16, n = 10). No storied structure observed. The tangential section is very poorly preserved, but a few rays were observed that appeared to have radial canals. Prismatic crystals present. Remarks—This specimen is most likely a very poorly preserved example of the Anacardiaceae morphotype. The length of the vessel elements may be underestimated if a tyloses mimicked an end wall.

Specimen—UF 18289-56307. Description—Transverse section poorly preserved. Perforation plates simple. Intervessel pits alternate averaging to 6.3 µm (SD = 0.8 µm, Range: 4.7–7.5 µm, n = 10). Vessel element length obscured. Rays 1-3 cells wide. Average ray height 190 µm (SD = 87, Range: 84–338 µm, n = 14). Rays per millimeter averages to 13 (Range: 10 to 20, n = 10). No storied structure observed. Radial canals present. Remarks—Possible Anacardiaceae, but too poorly preserved to know.

Specimen—UF 18289-56309. Description—Vessels arranged in short radial multiples or solitary. Intervessel pits alternate averaging to 5.7 µm (SD = 0.9 µm, Range: 3.8–7.1 µm, n = 10). Vessel ray pitting poorly preserved—either similar to intervessel pits or with reduced borders to simple and rounded. Fibers thin to thick walled. Rays mostly 1-2 seriate. The radial section too poorly preserved to determine the cellular composition. No storied structure observed.

576

Remarks—Possible Anacardiaceae type, but overall poor preservation.

Specimen—UF 18591-33020. Description—Growth ring boundaries absent. Wood is diffuse-porous with many solitary vessels. Radial multiples often with one large vessel and a few smaller vessels or a few small vessels sandwiched between two large anchoring vessels. Rare clusters; all vessels within a cluster contained between two adjacent rays. Solitary vessels not angular in outline. Vessels average to 86 µm (SD = 30 µm, Range: 33–145 µm, n = 30) in tangential diameter. Vessel frequency averages 21 mm2 (Range: 18 to 24 mm2, n = 6). Tyloses common. Fibers thin to thick walled. Fibers could not be distinguished from axial parenchyma in transverse section. Fibers and/or axial parenchyma cells vary from having solid, dark black lumens or having debris in between the cell walls. A few larger cells with open lumens also observed, likely representing parenchyma. However, the arrangement and distribution of axial parenchyma not determined. Rays 1-3 cells wide. Prismatic crystals visible in rays. Characters visible only in longitudinal section not available. Vulnerability Index—Vulnerability index is 4.2 for this specimen. Remarks—The pith is clearly visible on this specimen as the rays can be observed radiating out from a central area with a high concentration of large, solitary vessels. This suggests this specimen is a root, rather than a stem. Two approaches were used to estimate the specific gravity of this specimen. Specific gravity is 0.70 using the methods of Wheeler et al. (2007a), whereas the estimate is 0.99 using equation 1 of Martínez-Cabrera et al. (2012).

Specimen—UF 18591-33038. Description—Growth rings absent; wood diffuse-porous. Vessels solitary or in radial multiples of 2 to 4, occasionally longer. Solitary vessels rounded, not angular in outline. Mean tangential diameter of vessel lumina 59 µm (SD = 13 µm, Range: 31–88 µm, n = 30). Vessels per square millimeter ranges from 22 to 30 (avg. = 25, n = 6). Occasional tyloses. Fibers thin to thick- walled. Apotracheal parenchyma present, in radial lines. Rays mostly two cells wide. Radial canals present (not as common as some other examples of this morphotype—only one observed on the edge of the slide). Prismatic crystals common in ray cells. Vulnerability Index—Estimated vulnerability index is 2.4 for this specimen. Remarks—This specimen is most likely another poorly preserved example of the Anacardiaceae morphotype. Two approaches were used to estimate the specific gravity of this wood specimen. Specific gravity is estimated to be 0.79 using the methods of Wheeler et al. (2007a) and the estimate is 0.89 using equation 1 of Martínez-Cabrera et al. (2012).

Specimen—UF 18591-33044. Description—Growth rings absent; wood diffuse-porous. Vessels solitary or more frequently grouped in radial multiples of 2 to 4 with occasional small clusters and longer radial multiples (e.g., 8). Mean tangential diameter of vessels 70 µm (SD = 18 µm, Range: 32–100 µm, n = 30). Vessels per square millimeter average to 24 with a range from 18 to 26 (n = 6). Mean vessel element length is 89 µm (SD = 32 µm, Range: 45–174 µm, n = 24). Fiber walls very thin to medium in thickness. Rays 1 to 2 cells wide with 2 cells the most common condition. Likely radial canals observed (tangential section very poorly preserved). Prismatic crystals present in ray cells. Black circular bodies are also present in many of the ray cells. Vulnerability Index—Estimated vulnerability index is 2.9 for this specimen.

577

Remarks—The combination of characters suggests this specimen is another example of the Anacardiaceae wood type. The mean length of the vessel elements is quite low, which may be due to tyloses mimicking vessel element end walls. Two approaches were used to estimate the specific gravity of this wood specimen. Estimated specific gravity is 0.77 using the methods of Wheeler et al. (2007a), whereas the estimate is 0.94 using equation 1 as supplied by Martínez- Cabrera et al. (2012).

Indet. Family Unidentified & Unplaced Specimens

Specimen—UF 18591-33019. Description—Growth ring boundaries absent. Wood diffuse-porous with mostly solitary vessels and very rare radial multiples of 2, 3, or 4. Also, rare sub-tangentially aligned pairs of vessels, but this may represent the point where two end walls meet. Many vessels compressed, usually in the tangential direction, with a mean tangential diameter of 26 µm (SD = 7 µm, Range: 15–44 µm, n = 30). Vessel frequency ranges from 22-42 mm2 (n = 6) with an average of 32. Tyloses present, but not common. Fibers thin to thick walled. Poor preservation did not allow fibers to be distinguished from parenchyma or any ray characters to be determined. Vulnerability Index—This specimen has an estimated vulnerability index of 0.8. Remarks—The high proportion of solitary vessels helps distinguish this specimen from some others at BR, but poor preservation, especially in longitudinal view, does not permit a detailed description and taxonomic assignment. The transverse section view resembles that of the Canellaceae morphotype (UF 18591-33036); however, the mean vessel diameter is much smaller and vessel density is much greater in this specimen. These differences in quantitative characters suggest this specimen could be a small branch of the Canellaceae morphotype. Unfortunately, the fossil is too poorly preserved in the longitudinal direction for a full comparison. Nonetheless, the presence of vessels grouped in rare radial multiples in this specimen along with the other quantitative differences tentatively suggests they are not the same species. However, these differences could represent variation between or within individuals, but other characters including details about the perforation plates and rays would be needed. Also, the vulnerability index of this specimen (0.8) is much lower than the Canellaceae specimen (4.8).

Specimen—UF 18591-33037. Description—Transverse section distorted, but growth rings appear absent. Diffuse-porous with vessels arranged in radial multiples of 2 to 4 with rare multiples greater than four or solitary. Solitary vessels not angular in outline. Intervessel pits alternate. Intervessel pit size minute to small with an average of 4.3 µm (SD = 0.4 µm, Range: 3.9–5.3 µm, n = 10). Mean tangential diameter of vessel lumina 52 µm (SD = 21 µm, Range: 19–107 µm, n = 30). Vessels per square millimeter ranges from 18 to 38 with an average of 26 (n = 6). Some vessels obscured, possible tyloses. Fiber pits visible when they overlay vessels; pits are simple to minutely bordered. Fibers with thin to thick walls. Although the distorted transverse section did not allow for clear classification of the axial parenchyma, it may be present around the vessels. Rays frequently 2 cells wide, ranging to 3-4 cells wide, occasionally up to 6 cells wide. Vulnerability Index—Estimated vulnerability index is 2.0 for this specimen.

578

Remarks—Due to the distorted preservation of this specimen other characters could not be determined. However, it does not conform to the Canellaceae morphotype due to the regular vessel groupings.

Specimen—UF 18591-33046. Description—Transverse section poorly preserved; vessels solitary or in short radial multiples. No evidence for scalariform perforation plates observed, therefore likely simple. Intervessel pits poorly preserved, but appear alternate and small averaging 5.5 µm (SD = 0.6 µm, Range: 4.7–6.7 µm, n = 10). Some tyloses. Rays 1-2 cells wide, more frequently one. Body ray cells procumbent with 1-2 rows of upright or square marginal cells. Remarks—Few characters could be determined from this specimen making it difficult to compare to others. Of the Blue Rim angiosperm wood types, this specimen seems most similar to the Anacardiaceae type, but the preservation is poor on all section views.

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APPENDIX E CLAMP SCORE SHEET

Table E-1. Raw, untransformed CLAMP data.

Apex Base Shape Lami Length to Width Margin Character States Size Character States Character Characte Characte na Character States States r States r States

Number

Species Species

2:1 3:1 4:1

- - -

<1:1

Acute Acute

Specie Teeth

Ovate

Round

Lobed

Round

Elliptic

eth Close

Cordate

Unlobed Obovate

No Teeth

Attenuate

s / L:W L:W >4:1

L:W 1 L:W 2 L:W 3

Nanophyll

MesophyllI Emarginate

Microphyll I

Leptophyll I

Teeth Acute MesophyllII

Microphyll II

Leptophyll II

MesophyllIII

Teeth Round Microphyll III

Teeth Distant

Morph Teeth Regular

Teeth Irregular

Compound<50% otypes Teeth Compound HT 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 VCT 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 SR 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 HPT 1 1 1 1 1 1 1 1 1 1 1 4 AF 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 PC 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 6 GBT 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 7 TDA 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 8 /PS CBT 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 9 1 ATR 1 1 1 1 1 1 1 1 1 1 1 0 1 RL 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TT 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 GB 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3

580

1 TRB 1 1 1 1 1 1 1 1 1 4 1 TCE 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 SYZ 1 1 1 1 1 1 1 1 6 1 SYM 1 1 1 1 1 1 1 1 1 1 1 7 1 BTB 1 1 1 1 1 1 1 1 1 1 1 1 8 P 1 BTY 1 1 1 1 1 1 1 1 1 1 1 1 9 2 BTO 1 1 1 1 1 1 1 0 S

581

LIST OF REFERENCES

ACEVEDO-RODRÍGUEZ, P. 1988. Novelties in Serjania (Sapindaceae). Brittonia 40: 283-289.

ACEVEDO-RODRÍGUEZ, P. 1993. Systematics of Serjania (Sapindaceae). Part 1: A revision of Serjania sect. Platycoccus. Mem. New York Bot. Gard. 67: 1-93.

ALEXANDER, J. P., and B. J. BURGER. 2001. Stratigraphy and Taphonomy of Grizzly Buttes, Bridger Formation, and the Middle Eocene of Wyoming. In G. F. Gunnell [ed.], Eocene biodiversity : unusual occurrences and rarely sampled habitats Kluwer Academic/Plenum Publishers, New York.

ALLEN, S. E. 2011. Paleobotanical diversity at the Blue Rim sites of the Eocene Bridger Formation, southwestern Wyoming. GSA Annual Meeting Abstract Paper No. 120-15.

ALLEN, S. E. 2015a. Fossil palm flowers from the Eocene of the Rocky Mountain Region with affinities to Phoenix L. (Arecaceae: Coryphoideae). Int. J. Plant Sci. 176: 586-596.

ALLEN, S. E. 2015b. Leaf fossils from the Blue Rim flora of the Eocene Bridger Formation, southwestern Wyoming. Botany 2015, Edmonton, Alberta, Canada.

ALLEN, S. E., G. W. STULL, and S. R. MANCHESTER. 2015. Icacinaceae from the Eocene of western North America. Am. J. Bot. 102 725-744.

AMBWANI, A., and D. DUTTA. 2005. Seed-like structure in dinosaurian coprolite of Lameta Formation (Upper Cretaceous) at Pisdura, Maharashtra, India. Current Science 88: 352- 354.

ANDRADE, J. L., F. C. MEINZER, G. GOLDSTEIN, and S. A. SCHNITZER. 2005. Water uptake and transport in lianas and co-occurring trees of a seasonally dry tropical forest. Trees 19: 282-289.

APG. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Botanical Journal of the Linnean Society 161: 105- 121.

ARNOLD, C. A. 1936. The Occurrence of Cedrela in the Miocene of Western America. The American Midland Naturalist 17: 1018-1021.

ASMUSSEN, C. B., J. DRANSFIELD, V. DEICKMANN, A. S. BARFOD, J.-C. PINTAUD, and W. J. BAKER. 2006. A new subfamily classification of the palm family (Arecaceae): evidence from plastid DNA phylogeny. Botanical Journal of the Linnean Society 151: 15-38.

AWASTHI, N. 1992. Indian fossil legumes. In P. S. Herendeen AND D. L. Dilcher [eds.], Advances in Legume Systematics: Part 4. The Fossil Record, 225-250. The Royal Botanic Gardens, Kew.

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BAAS, P. 1983. Ecological patterns of xylem anatomy. In T. J. Givnish [ed.], On the economy of plant form and function: Proceedings of the Sixth Maria Moors Cabot Symposium, "Evolutionary Constraints on Primary Productivity: Adaptive Patters of Energy Capture in Plants", 327-352. Cambridge University Press, Cambridge.

BAAS, P., F. W. EWERS, S. D. DAVIS, and E. A. WHEELER. 2004. Evolution of xylem physiology. In A. R. Hemsley AND I. Poole [eds.], The Evolution of Plant Physiology, 273–295. Elsevier Academic Press, London.

BAILEY, I. W., and E. W. SINNOTT. 1915. A botanical index of Cretaceous and Tertiary climates. Science 41: 831-834.

BAILEY, I. W., and E. W. SINNOTT. 1916. The climate distribution of certain types of angiosperm leaves. American Journal of Botany 3: 24-39.

BAILEY, I. W., and R. A. HOWARD. 1941a. The comparative morphology of the Icacinaceae. I. Anatomy of the node and internode. Journal of the Arnold Arboretum 22: 125-132.

BAILEY, I. W., and R. A. HOWARD. 1941b. The comparative morpholgy of the Icacinaceae. II. Vessels. Journal of the Arnold Arboretum 22: 171-187.

BAKER, T. R., O. L. PHILLIPS, Y. MALHI, S. ALMEIDA, L. ARROYO, A. DI FIORE, T. ERWIN, et al. 2004. Variation in wood density determines spatial patterns in Amazonian forest biomass. Global Change Biology 10: 545-562.

BANDE, M. B., and U. PRAKASH. 1980. Fossil woods from the Tertiary of West Bengal, India. Geophytology 10: 146-157.

BARETTA-KUIPERS, T. 1981. Wood anatomy of Leguminosae: its relevance to taxonomy. In R. M. Polhill AND P. H. Raven [eds.], Advances in Legume Systematics 2, 677-705. Royal Botanic Gardens: Kew.

BARKLEY, F. A. 1937. A monographic study of Rhus and its immediate allies in North and Central America, including the West Indies. Annals of the Missouri Botanical Garden 24: 265-499.

BARRETT, J. W. 1995. Regional Silviculture of the United States. John Wiley & Sons, Inc., New York.

BARROW, S. C. 1998. A Monograph of Phoenix L. (Palmae: Coryphoideae). Kew Bulletin 53: 513-575.

BAY, K. W. 1969. Stratigraphy of Eocene sedimentary rocks in the Lysite Mountain Area Hot Springs, Fremont and Washakie Counties, Wyoming. PhD diss., University of Wyoming, Laramie.

BEERLING, D. J., and D. L. ROYER. 2011. Convergent Cenozoic CO2 history. Nature Geoscience 4: 418-420.

583

BERALDI-CAMPESI, H., S. R. S. CEVALLOS-FERRIZ, E. ELENA CENTENO-GARCÍA, C. ARENAS- ABAD, and L. P. FERNÁNDEZ. 2006. Sedimentology and paleoecology of an Eocene- Oligocene alluvial-lacustrine arid system, Southern Mexico. Sedimentary Geology 191: 227-254.

BERNARDELLO, G. 2007. A systematic survey of floral nectaries. In S. W. Nicolson, M. Nepi, AND E. Pacini [eds.], Nectaries and Nectar, 19-128. Springer, Dordrecht, The Netherlands.

BERRY, E. W. 1914. Fruits of a date palm in the Tertiary deposits of eastern Texas. American Journal of Science 187: 403-406.

BERRY, E. W. 1930. A flora of Green River age in the Wind River Basin of Wyoming, 55-81. United States Geological Survey Professional Paper 165-B, Washington, D.C., USA.

BLACK, C. C. 1967. Middle and Late Eocene Mammal Communities: A Major Discrepancy. Science 156: 62-64.

BONDE, S. D., M. S. KUMBHOJKAR, and R. T. AHER. 2000. Phoenicicaulon mahabalei gen. et. sp. nov., a sheathing leaf base of Phoenix from the Deccan Intertrappean beds of India. Geophytology 29: 11-16.

BOONCHAI, N. 2012. Systematic affinities and paleoenvironment of Eocene petrified woods from southwestern Wyoming, USA. PhD diss., Jilin University, Changchun, China.

BOONCHAI, N., and S. R. MANCHESTER. 2012. Systematic affinities of Early Eocene petrified woods from Big Sandy Reservoir, southwestern Wyoming Int. J. Plant Sci. 173: 209-227.

BOUCHAL, J. M., R. ZETTER, and T. DENK. 2016. Pollen and spores of the uppermost Eocene Florissant Formation, Colorado: a combined light and scanning electron microscopy study. Grana 55: 179-245.

BOUCHENAK-KHELLADI, Y., A. M. MUASYA, and H. P. LINDER. 2014. A revised evolutionary history of Poales: origins and diversification. Botanical Journal of the Linnean Society 175: 4-16.

BOUCHER, L. D., S. R. MANCHESTER, and W. S. JUDD. 2003. An Extinct Genus of Salicaceae based on twigs with attached flowers, fruits, and foliage from the Eocene Green River Formation of Utah and Colorado, USA. American Journal of Botany 90: 1389-1399.

BRADLEY, W. H. 1963. Paleolimnology. In D. G. Frey [ed.], Limnology in North America, 621- 652. University of Wisconsin Press, Madison.

BRADLEY, W. H. 1973. Oil Shale formed in Desert Environment: Green River Formation, Wyoming. Geological Society of America Bulletin 84: 1121-1124.

BRAND, L. R. 2007. Lacustrine Deposition in the Bridger Formation: Lake Gosiute Extended. The Mountain Geologist 44: 69-78.

584

BRETT, D. W. 1966. Fossil Wood of Anacardiaceae from the British Eocene. Paleontology 9: 360-364.

BRONGNIART, A. T. 1828. Prodrome d’une histoire des végétaux fossiles. F.G. Levrault Paris.

BROWN, R. W. 1929. Additions to the flora of the Green River Formation, 279-299. United States Department of the Interior Professional Paper 154-J, Washington, D.C., USA.

BROWN, R. W. 1934. The recognizable species of the Green River flora, 45-68. United States Department of the Interior Professional Paper 185-C, Washington, D.C., USA.

BROWN, R. W. 1937. Additions to some fossil floras of the Western United States, 163-186. United States Department of the Interior Professional Paper 186-J, Washington, D.C., USA.

BROWN, S., A. J. R. GILLESPIE, and A. E. LUGO. 1989. Biomass Estimation Methods for Tropical Forests with Applications to Forest Inventory Data. Forest Science 35: 881-902.

BRUNEAU, A., M. MERCURE, G. P. LEWIS, and P. S. HERENDEEN. 2008. Phylogenetic patterns and diversification in the caesalpinioid legumes. Botany 86: 697-718.

BUCHHEIM, H. P., L.R. BRAND, H.T. GOODWIN. 2000. Lacustrine to fluvial floodplain deposition in the Eocene Bridger Formation. Palaeogeography, Palaeoclimatology, Palaeoecology 162: 191–209.

BURNHAM, R. J. 1989. Relationships between standing vegetation and leaf litter in a paratropical forest: Implications for paleobotany. Review of Palaeobotany and Palynology 58: 5-32.

BURNHAM, R. J. 1994a. Paleoecological and Floristic Heterogeneity in the Plant-Fossil Record-- An Analysis Based on the Eocene of Washington. U.S. Geological Survey Bulletin 2085- B: B1-B36.

BURNHAM, R. J. 1994b. Patterns in tropical leaf litter and implications for angiosperm paleobotany. Review of Palaeobotany and Palynology 81: 99-113.

BURNHAM, R. J., and K. R. JOHNSON. 2004. South American paleobotany and the origins of neotropical rainforests. Phil. Trans. R. Soc. Lond. B 359: 1595-1610.

BURNHAM, R. J., S. L. WING, and G. G. PARKER. 1992. The reflection of deciduous forest communities in leaf litter: implications for autochthonous litter assemblages from the fossil record. Paleobiology 18: 30-49.

BŮŽEK, C. 1977. Date-palm seeds from the Lower Miocene of Central Europe. Vĕstník Ústředního ústavu geologického 52: 159-168.

BYNG, J. W., B. BERNARDINI, J. A. JOSEPH, M. W. CHASE, and T. M. A. UTTERIDGE. 2014. Phylogenetic relationships of Icacinaceae focusing on the vining genera. Botanical Journal of the Linnean Society 176: 277-294.

585

CAI, Z.-Q., S. A. SCHNITZER, and F. BONGERS. 2009. Seasonal differences in leaf-level physiology give lianas a competitive advantage over trees in a tropical seasonal forest. Oecologia 161: 25-33.

CANTINO, P. D., J. A. DOYLE, S. W. GRAHAM, W. S. JUDD, R. G. OLMSTEAD, D. E. SOLTIS, P. S. SOLTIS, et al. 2007. Towards a phylogenetic nomenclature of Tracheophyta. Taxon 56: E1-E44.

CARLQUIST, S. 1975a. Wood anatomy of Onagraceae, with notes on alternative modes of photosynthate movement in dicotyledon woods. Ann. Mo. Bot. Gard. 62: 386-424.

CARLQUIST, S. 1975b. Ecological Strategies of Xylem Evolution. University of California Press, Berkeley.

CARLQUIST, S. 1977. Ecological Factors in Wood Evolution: A Floristic Approach. Am. J. Bot. 64: 887-896.

CARLQUIST, S. 2012. How wood evolves: a new synthesis. Botany 90: 901-940.

CARROLL, A. R., A. C. DOEBBERT, A. L. BOOTH, C. P. CHAMBERLAIN, M. K. RHODES-CARSON, M. E. SMITH, C. M. JOHNSON, et al. 2008. Capture of high-altitude precipitation by a low- altitude Eocene lake, western U.S. Geology 36: 791-794.

CHADWICK, A., and T. YAMAMOTO. 1984. A paleoecological analysis of the petrified trees in the Specimen Creek Area of Yellowstone National Park, Montana, U.S.A. Palaeogeography, Palaeoclimatology, Palaeoecology 45: 39-48.

CHALONER, W. G., and G. T. CREBER. 1990. Do fossil plants give a climatic signal? Journal of the Geological Society, London 147: 343-350.

CHANDLER, M. E. J. 1957. The Oligocene Flora of the Bovey Tracey Lake Basin, Devonshire. Bulletin of the British Museum (Natural History) Geology 3: 7-123.

CHASE, M. W., S. ZMARZTY, M. D. LLEDÓ, K. J. WURDACK, S. M. SWENSEN, and M. F. FAY. 2002. When in Doubt, Put It in Flacourtiaceae: A Molecular Phylogenetic Analysis Based on Plastid rbcL DNA Sequences. Kew Bulletin 57: 141-181.

CHATTAWAY, M. 1951. The Development of Horizontal Canals in Rays. Australian Journal of Biological Sciences 4: 1-11.

CHAVE, J., D. COOMES, S. JANSEN, S. L. LEWIS, N. G. SWENSON, and A. E. ZANNE. 2009. Towards a worldwide wood economics spectrum. Ecology Letters 12: 351-366.

CHEN, I., and S. R. MANCHESTER. 2011. Seed Morphology of Vitaceae. International Journal of Plant Sciences 172: 1-35.

586

CHETEL, L., S. U. JANECKE, A. R. CARROLL, B. L. BEARD, C. M. JOHNSON, and B. S. SINGER. 2011. Paleographic reconstruction of the Eocene Idaho River, North American Cordillera. GSA Bulletin 123: 71-88.

CHETEL, L. M., and A. R. CARROLL. 2010. Terminal Infill of Eocene Lake Gosiute, Wyoming, U.S.A. Journal of Sedimentary Research 80: 492-514.

CHRISTENSEN, P. B. 1986. Pollen morphological studies in the Malvaceae. Grana 25: 95-117.

CLYDE, W. C., J.-P. ZONNEVELD, J. STAMATAKOES, G. F. GUNNELL, and W. S. BARTELS. 1997. Magnetostratigraphy across the Wasatchian/Bridgerian NALMA Boundary (Early to Middle Eocene) in the Western Green River Basin, Wyoming. The Journal of Geology 105: 657-669.

CLYDE, W. C., N. D. SHELDON, P. L. KOCH, G. F. GUNNELL, and W. S. BARTELS. 2001. Linking the Wasatchian/Bridgerian boundary to the Cenozoic Global Climate Optimum: new magnetostratigraphic and isotopic results from South Pass, Wyoming. Palaeogeography, Palaeoclimatology, Palaeoecology 167: 175-199.

COCKERELL, T. D. A. 1925. Plant and insect fossils from the Green River Eocene of Colorado. Proceedings U.S. National Museum 66: 1-12.

COIFFARD, C., B. GOMEZ, J. KVAC, and F. THEVENARD. 2006. Early Angiosperm Ecology: Evidence from the Albian-Cenomanian of Europe. Annals of Botany 98: 495-502.

COLE, R. D. 1975. Sedimentology and sulfur isotope geochemistry of Green River Formation (Eocene), Uinta Basin, Utah, Piceane Creek Basin, Colorado. PhD diss., University of Utah, Salt Lake City.

COLLINSON, M. E. 1992. The early fossil history of Salicaceae: a brief review. Proceedings of the Royal Society of Edinburgh 98B: 155-167.

COLLINSON, M. E., P. ANDREWS, and M. K. BAMFORD. 2009. Taphonomy of the early Miocene flora, Hiwegi Formation, Rusinga Island, Kenya. Journal of Human Evolution 57: 149- 162.

COLLINSON, M. E., S. R. MANCHESTER, and V. WILDE. 2012. Fossil fruits and seeds of the Middle Eocene Messel biota, Germany. Abhandlungen der Senckenberg Gesellschaft für Naturforschung 570: 1-249.

CONWENTZ, H. 1886. Die Angiospermen des Bernsteins. Naturforschenden Gesellschaft, Danzig.

COUVREUR, T. L. P., F. FOREST, and W. J. BAKER. 2011. Origin and global diversification patterns of tropical rain forests: inferences from a complete genus-level phylogeny of palms. BMC Biology 9: 1-12.

CRABTREE, D. R. 1987. Angiosperms of the northern Rocky Mountains: Albian to Campanian (Cretaceous) megafossil floras Annals of the Missouri Botanical Garden 74: 707-747.

587

CRANE, P. R. 1984. A re-evaluation of Cercidiphyllum-like plant fossils from the British early Tertiary. Botanical Journal of the Linnean Society 89: 199-230.

CRANE, P. R. 1987. Abelia-like fruits from the Palaeogene of Scotland and North America. Tertiary Research 9: 21-30.

CREPET, W. L., and G. D. FELDMAN. 1991. The Earliest Remains of Grasses in the Fossil Record. American Journal of Botany 78: 1010-1014.

CRONQUIST, A. 1981. An Integrated System of Classification of Flowering Plants. Columbia University Press, New York.

CURRANO, E. D., P. WILF, S. L. WING, C. C. LABANDEIRA, E. C. LOVELOCK, and D. L. ROYER. 2008. Sharply increased insect herbivory during the Paleocene-Eocene Thermal Maximum. PNAS 105: 1960-1964.

DAGHLIAN, C. P. 1981. A Review of the Fossil Record of Monocotyledons. The Botanical Review 47: 517-555.

DAHLGREN, R. M. T., H. T. CLIFFORD, and P. F. YEO. 1985. The Families of the Monocotyledons. Springer-Verlag, Berlin.

DECELLES, P. G. 1994. Late Cretaceous-Paleocene synorogenic sedimentation and kinematic history of the Sevier thrust belt, northeast Utah and southwest Wyoming. GSA Bulletin 106: 32-56.

DECHAMPS, R. 1987. Xylotomy of Fossil Wood from the Sahabi Formation. In N. T. Boaz, A. El-Arnauti, A. W. Gaziry, J. De Heinzelin, AND D. D. Boaz [eds.], Neogene Paleontology and Geology of Sahabi, 37-41. Alan R. Liss, Inc., New York.

DECHAMPS, R., and F. MAES. 1987. Paleoclimatic Interpretation of Fossil Wood from the Sahabi Formation In N. T. Boaz, A. El-Arnauti, A. W. Gaziry, J. De Heinzelin, AND D. D. Boaz [eds.], Neogene Paleontology and Geology of Sahabi, 43-81. Alan R. Liss, Inc., New York.

DECHAMPS, R., and F. MAES. 1990. Woody Plant Communities and Climate in the Pliocene of the Semliki Valley, Zaire. In N. T. Boaz [ed.], Evolution of Environments and Hominidae in the African Western Rift Valley, vol. 1, 71-94. Virginia Museum of Natural History Memoir, Martinsville.

DEMASON, D. A., K. W. STOLTE, and B. TISSERAT. 1982. Floral development in Phoenix dactylifera. Can. J. Bot. 60: 1437-1446.

DETTMAN, D. L., and K. C. LOHMANN. 2000. Oxygen isotope evidence for high-altitude snow in the Laramide Rocky Mountains of North America during the Late Cretaceous and Paleogene. Geology 28: 243-246.

588

DEVORE, M. L., K. B. PIGG, and W. WEHR. 2005. Systematics and phytogeography of selected Eocene Okanagan Highlands plants. Can. J. Earth Sci. 42: 205-214.

DEWALT, S. J., S. A. SCHNITZER, J. CHAVE, F. BONGERS, R. J. BURNHAM, Z. CAI, G. CHUYONG, et al. 2010. Annual rainfall and seasonality predict pan-tropical patterns of liana density and basal area. Biotropica 42: 309-317.

DEWALT, S. J., S. A. SCHNITZER, L. F. ALVES, F. BONGERS, R. J. BURNHAM, Z. CAI, W. P. CARSON, et al. 2015. Biogeographical pattern of liana abundance and diversity. In S. A. Schnitzer, F. Bongers, R. J. Burnham, AND F. E. Putz [eds.], Ecology of Lianas, 131- 146. John Wiley & Sons, Ltd, West Sussex, United Kingdom.

DICKEY, R. D., S. G. GILBERT, and C. M. GROPP. 1952. The Genus Aleurites in Florida. Bulletin University of Florida. Agricultural Experiment Station 503: 1-40.

DICKINSON, W. R., T. F. LAWTON, M. PECHA, S. J. DAVIS, G. E. GEHRELS, and R. A. YOUNG. 2012. Provenance of the Paleogene Colton Formation (Uinta Basin) and Cretaceous- Paleogene provenance evolution in the Utah foreland: Evidence from U-Pb ages of detrital zircons, paleocurrent trends, and sandstone petrofacies. Geosphere 8: 1-27.

DICKINSON, W. R., M. A. KLUTE, M. J. HAYES, S. U. JANECKE, E. R. LUNDIN, M. A. MCKITTRICK, and M. D. OLIVARES. 1988. Paleogeographic and paleotectonic settings of Laramide sedimentary basins in the central Rocky Mountain region. GSA Bulletin 100: 1023-1039.

DILLHOFF, R. M., E. B. LEOPOLD, and S. R. MANCHESTER. 2005. The McAbee flora of British Columbia and its relation to the Early-Middle Eocene Okanagan Highlands flora of the Pacific Northwest. Can. J. Earth Sci. 42: 151-166.

DIMICHELE, W. A., and R. A. GASTALDO. 2008. Plant Paleoecology in Deep Time 1. Annals of the Missouri Botanical Garden 95: 144-198.

DRANSFIELD, J., I. K. FERGUSON, and N. W. UHL. 1990. The Coryphoid Palms: Patterns of Variation and Evolution. Annals of the Missouri Botanical Garden 77: 802-815.

DRANSFIELD, J., N. W. UHL, C. B. ASMUSSEN, W. J. BAKER, M. M. HARLEY, and C. E. LEWIS. 2008. Genera Palmarum: The Evolution and Classification of Palms. Kew Publishing, UK.

EAMES, A. J. 1961. Morphology of the angiosperms. McGraw-Hill, New York, New York, USA.

ECKENWALDER, J. E. 1977. North American cottonwoods (Populus, Salicaceae) of Sections Abaso and Aigeiros. Journal of the Arnold Arboretum 58: 193-208.

ECKENWALDER, J. E. 1980. Foliar Heteromorphism in Populus (Salicaceae), a Source of Confusion in the Taxonomy of Tertiary Leaf Remains. Systematic Biology 5: 366-383.

589

ECKENWALDER, J. E. 1996. Systematics and evolution of Populus. In R. F. Stettler, H. D. Bradshaw Jr., P. E. Heilman, AND T. M. Hinckley [eds.], Biology of Populus and its implications for management and conservation, 7–32. NRC Research Press, National Research Council of Canada, Ottawa, Ontario, Canada.

ELLIS, B., D. C. DALY, L. J. HICKEY, K. R. JOHNSON, J. D. MITCHELL, P. WILF, and S. L. WING. 2009. Manual of Leaf Architecture. Cornell University Press, Ithaca, New York, USA.

EMRY, R. J. 1990. Mammals of the Bridgerian (middle Eocene) Elderberry Canyon Local Fauna of eastern Nevada. In T. M. Bown AND K. D. Rose [eds.], Dawn of the Age of Mammals in the Northern Part of the Rocky Mountain Interior, North America, 187-210. Geological Society of America Special Paper 243.

ENGEL, M. S. 2001. A Monograph of the Baltic Amber Bees and Evolution of the Apoidea (Hymenoptera). Bulletin of the American Museum of Natural History 259: 1-192.

ENGLER, A. 1893. Icacinaceae In A. Engler AND K. Prantl [eds.], Die natürlichen Pflanzenfamilien, vol. III, 233–257. Wilhelm Engelmann, Leipzig, Germany.

ESPINOZA DE PERNÍA, N., and J. L. MELANDRI. 2006. Wood anatomy of the tribe Caesalpinieae (Leguminosae, Caesalpinioideae) in Venezuela. IAWA Journal 27: 99-114.

EUGSTER, H. P., and L. A. HARDIE. 1975. Sedimentation in an Ancient Playa-Lake Complex: The Wilkins Peak Member of the Green River Formation of Wyoming. Geological Society of America Bulletin 86: 319-334.

EWERS, F. W., J. M. EWERS, A. L. JACOBSEN, and J. LÓPEZ-PORTILLO. 2007. Vessel Redundancy: Modeling Safety in Numbers. IAWA Journal 28: 373-388.

FAEGRI, K., J. IVERSEN, P. E. KALAND, and K. KRZYWINSKI. 1989. Textbook of Pollen Analysis. John Wiley & Sons, New York.

FALL, P. L. 1992. Spatial patterns of atmospheric pollen dispersal in the Colorado Rocky Mountains, USA. Review of Palaeobotany and Palynology 74: 293-313.

FAN, M., and D. L. DETTMAN. 2009. Late Paleocene high Laramide ranges in northeast Wyoming: Oxygen isotope study of ancient river water. Earth and Planetary Science Letters 286: 110-121.

FAN, M., and B. CARRAPA. 2014. Late Cretaceous-early Eocene Laramide uplift, exhumation, and basin subsidence in Wyoming: Crustal responses to flat slab subduction. Tectonics 33: 1-21.

FARJON, A., and B. T. STYLES. 1997. Pinus (Pinaceae). Flora Neotropica 75: 1-291.

FAY, M. F. 1993. Icacina oliviformis (Icacinaceae). A close look at an underexploited food plant. III. Ecology and Production Economic Botany 47: 163-170.

590

FELDPAUSCH, T. R., L. BANIN, O. L. PHILLIPS, T. R. BAKER, S. L. LEWIS, C. A. QUESADA, K. AFFUM-BAFFOE, et al. 2011. Height-diameter allometry of tropical forest trees. Biogeosciences 8: 1081-1106.

FERGUSON, I. K., and M. M. HARLEY. 1993. The significance of new and recent work on pollen morphology in the Palmae. Kew Bulletin 48: 205-243.

FERRUCCI, M. S., and P. ACEVEDO-RODRÍGUEZ. 2005. Three new species of Serjania (Sapindaceae) from South America. Systematic Botany 30: 153-162.

FERRUCCI, M. S., and J. P. COULLERI. 2013. Serjania lucianoi (Sapindaceae: Paullinieae), a new species from northern Bahia, Brazil. Systematic Botany 38: 172-177.

FICHTLER, E., and M. WORBES. 2012. Wood anatomical variables in tropical trees and their relation to site conditions and individual tree morphology. IAWA Journal 33: 119-140.

FOREST, C. E., J. A. WOLFE, P. MOLNAR, and K. A. EMANUEL. 1999. Paleoaltimetry incorporating atmospheric physics and botanical estimates of paleoclimate. GSA Bulletin 111: 497-511.

FREDERIKSEN, N. O. 1980. Sporomorphs from the Jackson Group (Upper Eocene) and Adjacent Strata of Mississippi and Western Alabama. Geological Survey Professional Paper 1084.

FRICKE, H. C. 2003. Investigation of early Eocene water-vapor transport and paleoelevation using oxygen isotope data from geographically widespread mammal remains. GSA Bulletin 115: 1088-1096.

FRICKE, H. C., and S. L. WING. 2004. Oxygen isotope and paleobotanical estimates of temperature and δ18O-latitude temperature gradients over North America during the Early Eocene. American Journal of Science 304: 612-635.

FRITZ, W. J., and L. H. FISK. 1978. Eocene petrified woods from one unit of the Amethyst Mountain "fossil forest". Northwest Geology 7: 10-19.

FURNESS, C. A., and P. J. RUDALL. 2006. Comparative structure and development of pollen and tapetum in Pandanales. International Journal of Plant Sciences 167: 331-348.

GALLANT, J. B., J. R. KEMP, and C. R. LACROIX. 1998. Floral development of dioecious staghorn sumac, Rhus hirta (Anacardiaceae). International Journal of Plant Sciences 159: 539- 549.

GASSON, P., C. TRAFFORD, and B. MATTHEWS. 2003. Wood Anatomy of Caesalpinioideae. In B. B. Klitgaard AND A. Bruneau [eds.], Advances in Legume Systematics 10, 63-93. Royal Botanic Gardens, Kew.

GASTALDO, R. A. 1992. Taphonomic considerations for plant evolutionary investigations. Palaeobotanist 41: 211-223.

591

GASTALDO, R. A., and A.-Y. HUC. 1992. Sediment Facies, Depositional Environments, and Distribution of Phytoclasts in the Recent Mahakam River Delta, Kalimantan, Indonesia. Palaios 7: 574-590.

GENTRY, A. H. 1991. The distribution and evolution of climbing plants. In F. E. Putz AND H. A. Mooney [eds.], The Biology of Vines, 3–49. Cambridge University Press, Cambridge, United Kingdom.

GHAZANFAR, S. A. 2002. A new species of Rhus (Anacardiaceae) from the Sultanate of Oman, Arabia. Kew Bulletin 57: 491-494.

GIVINISH, T. J. 1984. Leaf and canopy adaptations in tropical forests. In E. Medina, H. A. Mooney, AND C. Vázquez-Yánes [eds.], Physiognomic interpretations of plants of the wet tropics, vol. 12, Tasks for Vegetation Science, 51-84. The Hague & W. Junk, Boston.

GOTTWALD, H. 1992. Hölzer aus marinen sanden des oberen Eozän vos Helmstedt (Niedersachsen). Palaeontographica Abt. B 225: 27-103.

GRANDE, L. 2013. The Lost World of Fossil Lake: Snapshots from Deep Time. University of Chicago Press, Chicago.

GREENWOOD, D. R., and S. L. WING. 1995. Eocene continental climates and latitudinal temperature gradients. Geology 23: 1044-1048.

GREENWOOD, D. R., S. B. ARCHIBALD, R. W. MATHEWES, and P. T. MOSS. 2005. Fossil biotas from the Okanagan Highlands, southern British Columbia and northeastern Washington State: climate and ecosystems across an Eocene landscape. Can. J. Earth Sci. 42: 167- 185.

GREGORY-WODZICKI, K. M. 1997. The Late Eocene House Ranch Flora, Sevier Desert, Utah: Paleoclimate and Paleoelevation. Palaios 12: 552-567.

GREGORY, M., I. POOLE, and E. A. WHEELER. 2009. Fossil dicot wood names: an annotated list with full bibliography. IAWA Journal Supplement 6: 1-220.

GROLL, P. E., and J. R. STEIDTMANN. 1987. Fluvial response to Eocene tectonism, the Bridger Formation, southern Wind River Range, Wyoming In F. G. Ethridge, R. M. Flores, AND M. D. Harvey [eds.], Recent Developments in Fluvial Sedimentology, vol. 39, Special Publications. Society of Economic Paleontologists and Mineralogists, Tulsa, OK.

GUNNELL, G. F. 1997. Wasatchian-Bridgerian (Eocene) paleoecology of the western interior of North America: changing paleoenvironments and taxonomic composition of omomyid (Tarsiiformes) primates. Journal of Human Evolution 32: 105-132.

GUNNELL, G. F. 1998. Mammalian fauna from the the Lower Bridger Formation (Bridger A, Early Middle Eocene) of the southern Green River Basin, Wyoming. Contributions from the Museum of Paleontology University of Michigan 30: 83-130.

592

GUNNELL, G. F., and W. S. BARTELS. 1994. Early Bridgerian (middle Eocene) vertebrate paleontology and paleoecology of the southern Green River Basin, Wyoming. Rocky Mountain Geology 30: 57-70.

GUNNELL, G. F., and W. S. BARTELS. 2001. Basin Margins, Biodiversity, Evolutionary Innovations, and the Origin of New Taxa. In G. F. Gunnell [ed.], Eocene Biodiversity: Unusual Occurrences and Rarely Sampled Habitats, vol. 18, Topics in Geobiology, 403- 432. Kluwer Academic/Plenum Publishers New York.

GUNNELL, G. F., P. C. MURPHEY, R. K. STUCKY, K. E. B. TOWNSEND, P. ROBINSON, J.-P. ZONNEVELD, and W. S. BARTELS. 2009. Biostratigraphy and Biochronology of the latest Wasatchian, Bridgerian, and Uintan North American Land Mammal "Ages". Museum of Northern Arizona Bulletin 65: 279-330.

GUSHULACK, C. A. C., C. K. WEST, and D. R. GREENWOOD. 2016. Paleoclimate and precipitation seasonality of the Early Eocene McAbee megaflora, Kamloops Group, British Columbia. Can. J. Earth Sci. 53: 591-604.

HAHN, W. J. 2002. A Molecular Phylogentic Study of the Palmae (Arecaceae) Based on atpB, rbcL, and 18S nrDNA Sequences. Syst. Biol. 51: 92-112.

HALL, S. A. 1990. Pollen deposition and vegetation in the southern Rocky Mountains and southwest Plains, USA. Grana 29: 47-61.

HAMZEH, M., and S. DAYANANDAN. 2004. Phylogeny of Populus (Salicaceae) based on nucelotide sequences of chloroplast trnT-trnF region and nuclear rDNA American Journal of Botany 91: 1398-1408.

HAMZEH, M., P. PÉRINET, and S. DAYANANDAN. 2006. Genetic Relationships among Species of Populus (Salicaceae) Based on Nuclear Genomic Data. Journal of the Torrey Botanical Society 133: 519-527.

HANLEY, J. H. 1974. Systematics, paleoecology, and biostratigraphy of nonmarine Mollusca from the Green River and Wasatch Formations (Eocene), southwestern Wyoming and northwestern Colorado. PhD diss., University of Wyoming, Laramie.

HANLEY, J. H. 1976. Paleosynecology of nonmarine Mollusca from the Green River and Wasatch Formations. In R. W. Scott AND R. R. West [eds.], Structure and classifications of paleocommunities, 235-261. Dowden, Hutchinson & Ross, Stroudsburg, PA.

HANLEY, J. H. 1977. Lithostratigraphic relations, nonmarine Mollusca, and depostional environments of a portion of the Green River and Wasatch Formations south of the Rock Springs uplift, Sweetwater County, Wyoming, with appendices of measured stratigraphic sections. In Interior [ed.]. U.S.G.S.

HARLEY, M. M. 1990. Occurrence of simple, tectate, monosulcate or trichotomosulcate pollen grians within the Palmae. Review of Palaeobotany and Palynology 64: 137-147.

593

HARLEY, M. M. 1997. Ultrastructure of pollen from some Eocene Palm flowers (Messel, Germany). Proceedings of the 4th EPPC 58: 193-209.

HARLEY, M. M. 2006. A summary of fossil records for Arecaceae. Botanical Journal of the Linnean Society 151: 39-67.

HARLEY, M. M., and W. J. BAKER. 2001. Pollen aperture morphology in Arecaceae: application within phylogenetic analyses, and a summary of the fossil record of palm-like pollen. Grana 40: 45-77.

HASTON, E., J. E. RICHARDSON, P. F. STEVENS, M. W. CHASE, and D. J. HARRIS. 2009. The Linear Angiosperm Phylogeny Group (LAPG) III: a linear sequence of the families in APG III. Bot. J. Linn. Soc. 161: 128-131.

HAWES, J. E., and C. A. PERES. 2013. Ecological correlates of trophic status and frugivory in neotropical primates. Oikos: 1-13.

HENRY, C. D., N. H. HINZ, J. E. FAULDS, J. P. COLGAN, D. A. JOHN, E. R. BROOKS, E. J. CASSEL, et al. 2012. Eocene-Early Miocene paleotopography of the Sierra Nevada-Great Basin-Nevadaplano based on widespread ash-flow tuffs and paleovalleys. Geosphere 8: 1-27.

HERENDEEN, P. S. 2000. Structural evolution in the Caesalpinioideae (Leguminosae). In P. S. Herendeen AND A. Bruneau [eds.], Advances in Legume Systematics 9, 45-64. Royal Botanic Gardens, Kew.

HERENDEEN, P. S., A. BRUNEAU, and G. P. LEWIS. 2003. Phylogenetic relationships in caesalpinioid legumes: a preliminary analysis based on morphological and molecular data. In B. B. Klitgaard AND A. Bruneau [eds.], Advances in Legume Systematics 10, 37-62. Royal Botanic Gardens, Kew.

HERMANN, R. K. 1985. The genus Pseudotsuga: Ancestral history and past distribution. Forest Research Laboratory, Oregon State University, Corvallis.

HERMSEN, E. J. 2005. The fossil record of Iteaceae and Grossulariaceae in the Cretaceous and Tertiary of the United States and Canada. Ph.D. diss., Cornell University, Ithaca, NY.

HICKEY, L. J. 1977. Stratigraphy and Paleobotany of the Golden Valley Formation (Early Tertiary) of Western North Dakota. GSA Memoirs 150: 1-296.

HILTON, J., J. B. RIDING, and G. W. ROTHWELL. 2016. Age and identity of the oldest pine fossils. Geology Forum: e400-e401.

HOLDRIDGE, L. R. 1967. Life Zone Ecology. Tropical Science Center, San Jose, Costa Rica.

HOWARD, R. A. 1942. Studies of the Icacinaceae IV. Considerations of the new world genera. Contributions from the Gray Herbarium of Harvard University 142: 3-60.

594

HOWARD, R. A. 1979. The Petiole. In C. R. Metcalfe AND L. Chalk [eds.], Anatomy of the Dicotyledons, vol. I, 88-96. Clarendon Press, Oxford, United Kingdom.

HU, Y. S., and F. H. WANG. 1984. Anatomical studies of Cathaya (Pinaceae). Am. J. Bot. 71: 727-735.

HUA, P., and R. A. HOWARD. 2008. Icacinaceae. In Z. Y. Wu, P. H. Raven, AND D. Y. Hong [eds.], Flora of China, vol. 11, 505-514. Science Press and Missouri Botanical Garden Press, Beijing, China and St. Louis, Missouri, USA.

HUBER, M., and R. CABALLERO. 2011. The early Eocene equable climate problem revisited. Clim. Past 7: 603-633.

HUFF, P. M., P. WILF, and E. J. AZUMAH. 2003. Digital Future for Paleoclimate Estimation from Fossil Leaves? Preliminary Results. Palaios 18: 266-274.

HUTCHINSON, J. 1964. The Genera of Flowering Plants. Oxford University Press, London.

HUTCHINSON, J. 1967. The Genera of Flowering Plants. Oxford University Press, London.

HYLAND, E., and N. D. SHELDON. 2013. Coupled CO2-climate response during the Early Eocene Climatic Optimum. Palaeogeography, Palaeoclimatology, Palaeoecology 369: 125-135.

INSIDEWOOD. 2004-onwards. Published on the Internet. http://insidewood.lib.ncsu.edu/search

JACOBS, B. F. 2004. Palaeobotanical studies from tropical Africa: relevance to the evolution of forest, woodland and savannah biomes. Philosophical Transactions of the Royal Society of London, B, Biological Sciences 359: 1573-1583.

JACOBS, B. F., and P. S. HERENDEEN. 2004. Eocene dry climate and woodland vegetation in tropical Africa reconstructed from fossil leaves from northern Tanzania. Palaeogeography, Palaeoclimatology, Palaeoecology 213: 115-123.

JAGELS, R., B. A. LEPAGE, and M. JIANG. 2001. Definitive identification of Larix (Pinaceae) wood based on anatomy from the middle Eocene Axel Heiberg Island, Canadian High Arctic. IAWA Journal 22: 73-83.

JANSSEN, C. R. 1966. Recent pollen spectra from the deciduous and coniferous-deciduous forests of northeastern Minnesota: A study in pollen dispersal. Ecology 47: 804-825.

JOHNSON, K. R. 1989. High-resolution Megafloral Biostratigraphy Spanning the Cretaceous- Tertiary Boundary in the Northern Great Plains. PhD diss., Yale University, New Haven.

JOHNSON, K. R., and C. PLUMB. 1995. Common plant fossils from the Green River Formation at Douglas Pass, Colorado, and Bonanza, Utah. In W. R. Averett [ed.], The Green River Formation in the Piceance Creek and Eastern Uinta Basins, 121-130. Grand Junction Geological Society Grand Junction, CO.

595

JONES, E., D. A. SIMPSON, T. R. HODKINSON, M. W. CHASE, and J. A. N. PARNELL. 2007. The Juncaceae-Cyperaceae interface: A combined plastid sequence analysis. Aliso 23: 55-61.

JUDD, W. S. 1997. The Flacourtiaceae in the southeastern United States. Harvard Papers in Botany 10: 65-79.

JUDD, W. S., C. S. CAMPBELL, E. A. KELLOGG, P. F. STEVENS, and M. J. DONOGHUE. 2008. Plant Systematics: A Phylogenetic Approach. Third ed. Sinauer Associates, Inc., Sunderland, MA.

KALÁCSKA, M., J. C. CALVO-ALVARADO, and G. A. SÁNCHEZ-AZOFEIFA. 2005. Calibration and assessment of seasonal changes in leaf area index of a tropical dry forest in different stages of succession. Tree Physiology 25: 733-744.

KÅREHED, J. 2001. Multiple origin of the tropical forest tree family Icacinaceae. American Journal of Botany 88: 2259-2274.

KAZDA, M. 2015. Liana-nutrient relations. In S. A. Schnitzer, F. Bongers, R. J. Burnham, AND F. E. Putz [eds.], Ecology of Lianas, 309-322. John Wiley & Sons, Ltd., West Sussex, United Kingdom.

KEARNS, D. M., W. W. THOMAS, G. C. TUCKER, R. KRAL, K. CAMELBEKE, D. A. SIMPSON, A. A. REZNICEK, et al. 1998. Cyperaceae. In P. E. Berry, B. K. Holst, AND K. Yatskievych [eds.], Flora of the Venezuelan Guayana, 486-663. Missouri Botanical Garden Press, St, Louis.

KEDVES, M. 1980. Morphological investigation of recent Palmae pollen grains. Acta Botanica Academiae Scientiarum Hungaricae 26: 339-373.

KISTNER, F. B. 1973. Stratigraphy of the Bridger Formation in the Big Island-Blue Rim Area, Sweetwater County, Wyoming. Master of Science, University of Wyoming, Laramie, Wyoming, USA.

KLITGÅRD, B. B., and G. P. LEWIS. 2010. Neotropical Leguminosae (Caesalpinioideae) http://www.kew.org/science/tropamerica/neotropikey/families/Leguminosae_(Caesalpini oideae).htm. In W. Milliken, B. Klitgård, AND A. Baracat [eds.], Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.

KNOBLOCH, E., and D. H. MAI. 1986. Monographie der früchte und samen in der Kreide von Mitteleuropa. Rozpr Ustred Ustav Geol Praha 47: 1-219.

KNOWLTON, F. H. 1899. Fossil Flora of the Yellowstone National Park, 651-791. Government Printing Office, Washington.

KOTTEK, M., J. GRIESER, B. C., B. RUDOLF, and F. RUBEL. 2006. World Map of the Köppen- Geiger climate classification updated. Meteorologische Zeitschrift 15: 259-263.

596

KOVACH, W. L., and R. A. SPICER. 1996. Canonical correspondence analysis of leaf physiognomy: A contribution to the development of a new palaeoclimatological tool. Palaeoclimates 2: 125-138.

KOWALSKI, E. A., and D. L. DILCHER. 2003. Warmer paleotemperatures for terrestrial ecosystems. PNAS 100: 167-170.

KRISHTALKA, L., R. M. WEST, C. C. BLACK, M. R. DAWSON, J. J. FLYNN, W. D. TURNBULL, R. K. STUCKY, et al. 1987. Eocene (Wasatchian through Duchesnean) Biochronology of North America. In M. O. Woodburne [ed.], Cenozoic Mammals of North America, 77- 117. University of California Press, Berkeley.

KRUSE, H. O. 1954. Some Eocene Dicotyledonous Woods from Eden Valley, Wyoming. Ohio Journal of Science 54: 243-268.

KUIPER, K. F., A. DEINO, F. J. K. HILGEN, W., P. R. RENNE, and J. R. WIJBRANS. 2008. Synchonizing rock clocks of Earth history. Science 320: 500-504.

KVAČEK, Z., and C. BUŽEK. 1995. Endocarps and foliage of the flowering plant family Icacinaceae from the Tertiary of Europe. Tertiary Research 15: 121-138.

KVAČEK, Z., L. HABLY, and S. R. MANCHESTER. 2001. Sloanea (Elaeocarpaceae) fruits and foliage from the Early Oligocene of Hungry and Slovenia. Palaeontographica Abt. B 259: 113-124.

LABANDEIRA, C. C., B. A. LEPAGE, and A. H. JOHNSON. 2001. A Dendroctonus bark engraving (Coleoptera: Scolytidae) from a middle Eocene Larix (Coniferales: Pinaceae): early or delayed colonization? Am. J. Bot. 88: 2026-2039.

LABANDEIRA, C. C., P. WILF, K. R. JOHNSON, and F. MARSH. 2007. Guide to Insect (and Other) Damage Types on Compressed Plant Fossils, 25. Smithsonian Institution, Washington, DC.

LABAT, J.-N., E. EL-ACHKAR, and R. RABEVOHITRA. 2006. Révision synoptique du genre Pyrenacantha (Icacinaceae) à Madagascar. Adansonia 28: 389-404.

LADD, P. G. 1977. Pollen Morphology of Some Members of the Restionaceae and Related Families, with Notes on the Fossil Record. Grana 16: 1-14.

LARCHER, W., and A. WINTER. 1981. Frost susceptibility of palms: Experimental data and their interpretation. Principes 25: 143-152.

LEOPOLD, E. B., and H. D. MACGINITIE. 1972. Development and Affinities of Tertiary Floras in the Rocky Mountains. In A. Graham [ed.], Floristics and Paleofloristics of Asia and Eastern North America. Elsevier Publishing Company, Amsterdam.

LEPAGE, B. A., and J. F. BASINGER. 1991. A new species of Larix (Pinaceae) from the early Tertiary of Axel Heiberg Island, Arctic Canada. Rev. Palaeobot. Palynol. 70: 89-111.

597

LESQUEREUX, L. 1878. Contributions to the fossil flora of the Western Territories. Part II. The Tertiary flora. United States Geological Survey, vol. VII, Washington, D.C., USA.

LESQUEREUX, L. 1883. Contributions to the fossil flora of the Western Territories. Part III. The Cretaceous and Tertiary floras. United States Geological Survey, vol. VIII, Washington, D.C., USA.

LEWIS, G., B. SCHRIRE, B. MACKINDER, and M. LOCK. 2005-onwards. Legumes of the World Online http://www.kew.org/science-conservation/research-data/resources/legumes-of- the-world.

LILLEGRAVEN, J. A. 2015. Late Laramide tectonic fragmentation of the eastern greater Green River Basin, Wyoming. Rocky Mountain Geology 50: 30-118.

LINDER, H. P., and I. K. FERGUSON. 1985. On the pollen morphology and phylogeny of the Restionales and Poales. Grana 24: 65-76.

LINDER, H. P., and P. J. RUDALL. 2005. Evolutionary History of Poales. Annu. Rev. Ecol. Syst. 36: 107-124.

LITTLE, S. A., S. W. KEMBEL, and P. WILF. 2010. Paleotemperature Proxies from Leaf Fossils Reinterpreted in Light of Evolutionary History. PLoS ONE 5: 1-8.

LIU, X., S. R. MANCHESTER, and J. JIN. 2014. Alnus subgenus Alnus in the Eocene of western North America based on leaves, associated catkins, pollen, and fruits. American Journal of Botany 101: 1925-1943.

LIU, Y.-S., and J. F. BASINGER. 2000. Fossil Cathaya (Pinaceae) pollen from the Canadian High Arctic. Int. J. Plant Sci. 161: 829-847.

LPWG. 2013a. Towards a new classification system for legumes: Progress report from the International Legume Conference. South African Journal of Botany 89: 3-9.

______. 2013b. Legume phylogeny and classification in the 21st century: Progress, prospects and lessons for other species-rich clades. Taxon 62: 217-248.

______. 2017. A new subfamily classification of the Leguminosae based on a taxonomically comprehensive phylogeny. Taxon 66: 44-77.

LUO, Y., L. LU, A. H. WORTLEY, D. LI, H. WANG, and S. BLACKMORE. 2015. Evolution of angiosperm pollen. 3. Monocots. Ann. Missouri Bot. Gard. 101: 406-455.

LYNCH, E. A. 1996. The ability of pollen from small lakes and ponds to sense fine-scale vegetation patterns in the Central Rocky Mountains, USA. Review of Palaeobotany and Palynology 94: 197-210.

MABBERLEY, D. J. 2008. Mabberley's Plant-Book. Third ed. Cambridge University Press, New York.

598

MACGINITIE, H. D. 1941. A Middle Eocene flora from the Central Sierra Nevada. Carnegie Institution of Washington, Washington, D.C., USA.

MACGINITIE, H. D. 1969. The Eocene Green River Flora of Northwestern Colorado and Northeastern Utah, 1-202. University of California Press, Berkeley, California, USA

MACGINITIE, H. D. 1974. An Early Middle Eocene flora from the Yellowstone-Absaroka Volcanic Province, northwestern Wind River Basin, Wyoming, 1-103. University of California Publications in Geological Science, Berkeley, California, USA.

MAGALLÓN-PUEBLA, S., and S. R. S. CEVALLOS-FERRIZ. 1994a. Latest occurrence of the extinct genus Cedrelospermum (Ulmaceae) in North America: Cedrelospermum manchesteri from Mexico. Review of Palaeobotany and Palynology 81: 115-128.

MAGALLÓN-PUEBLA, S., and S. R. S. CEVALLOS-FERRIZ. 1994b. Fossil legume fruits from tertiary strata of Puebla, Mexico. Can. J. Bot. 72: 1027-1038.

MAGALLÓN-PUEBLA, S., and S. R. S. CEVALLOS-FERRIZ. 1994c. Eucommia constans n. sp. fruits from Upper Cenozoic strata of Puebla, Mexico: Morphological and anatomical comparison with Eucommia ulmoides Oliver. Int. J. Plant Sci. 155: 80-95.

MAI, D. H. 1976. Fossile Früchte und Samen aus dem Mitteleozän des Geiseltales. Abhandlungen der Zentralen Geologischen Instituts 26: 93-149.

MAMBRÍN, M. V., M. M. AVANZA, and M. S. FERRUCCI. 2010. Análisis morfológico y morfométrico del polen de Corchorus, Heliocarpus, Luehea, Mollia y Triumfetta (Malvaceae, Grewioideae) en la región austral de américa del sur. Darwiniana 48: 45-58.

MANCHESTER, S. R. 1986. Vegetative and reproductive morphology of an extinct plane tree (Platanaceae) from the Eocene of Western North America. Botanical Gazette 147: 200- 226.

MANCHESTER, S. R. 1989. Attached reproductive and vegetative remains of the extinct American-European genus Cedrelospermum (Ulmaceae) from the early Tertiary of Utah and Colorado. American Journal of Botany 76: 256-276.

MANCHESTER, S. R. 1992. Flowers, fruits, and pollen of Florissantia, an extinct malvalean genus from the Eocene and Oligocene of western North America. American Journal of Botany 79: 996-1008.

MANCHESTER, S. R. 1994. Fruits and seeds of the middle Eocene Nut Beds flora, Clarno Formation, Oregon. Palaeontographica Americana 58: 1-205.

MANCHESTER, S. R. 1999. Biogeographical relationships of North American Tertiary floras. Annals of the Missouri Botanical Garden 86: 472-522.

MANCHESTER, S. R., and M. S. ZAVADA. 1987. Lygodium foliage with intact sorophores from the Eocene of Wyoming. Botanical Gazette 148: 392-399.

599

MANCHESTER, S. R., and B. H. TIFFNEY. 1993. Fossil fruits of Pyrenacantha and related Phytocreneae (Icacinaceae) in the Paleogene of North America, Europe, and Africa. American Journal of Botany Abstracts 80: 91.

MANCHESTER, S. R., and E. J. HERMSEN. 2000. Flowers, fruits, seeds, and pollen of Landeenia gen. nov., An extinct sapindalean genus from the Eocene of Wyoming. Am. J. Bot. 87: 1909-1914.

MANCHESTER, S. R., and E. A. WHEELER. 2006. Silicified woods from the Early Middle Eocene Bridger Formation in southwestern Wyoming, USA. Botany, California State University - Chico.

MANCHESTER, S. R., and E. ZASTAWNIAK. 2007. Fruit with perianth remains of Chaneya Wang & Manchester (extinct Rutaceae) in the Upper Miocene of Sośnica, Poland. Acta Palaeobotanica 47: 253-259.

MANCHESTER, S. R., and K. B. PIGG. 2008. The Eocene mystery flower of McAbee, British Columbia. Botany 86: 1034-1038.

MANCHESTER, S. R., and E. L. O'LEARY. 2010. Phylogenetic Distribution and Identification of Fin-winged Fruits. Bot. Rev. 76: 1-82.

MANCHESTER, S. R., D. L. DILCHER, and W. D. TIDWELL. 1986. Interconnected reproductive and vegetative remains of Populus (Salicaceae) from the middle Eocene Green River Formation, northeastern Utah. American Journal of Botany 73: 156-160.

MANCHESTER, S. R., D. L. DILCHER, and S. L. WING. 1998. Attached leaves and fruits of myrtaceous affinity from the Middle Eocene of Colorado. Rev. Palaeobot. Palynol. 102: 153-163.

MANCHESTER, S. R., W. S. JUDD, and B. HANDLEY. 2006. Foliage and Fruits of Early Poplars (Salicaceae: Populus) from the Eocene of Utah, Colorado, and Wyoming. Int. J. Plant Sci. 167: 897-908.

MANDER, L., and S. W. PUNYASENA. 2014. On the taxonomic resolution of pollen and spore records of Earth's vegetation. International Journal of Plant Sciences 175: 931-945.

MARTIN, R. D. 2003. Combing the primate record. Nature 422: 388-391.

MARTÍNEZ-CABRERA, H. I., E. ESTRADA-RUIZ, C. CASTAÑEDA-POSADAS, and D. WOODCOCK. 2012. Wood specific gravity estimation based on wood anatomical traits: Inference of key ecological characteristics in fossil assemblages. Rev. Palaeobot. Palynol. 187: 1-10.

MATTHEW, W. D. 1909. The Carnivora and Insectivora of the Bridger Basin, middle Eocene. American Museum of Natural History Memoir 9: 291-567.

600

MATTHIAS, I., and T. GIESECKE. 2014. Insights into pollen source area, transport and deposition from modern pollen accumulation rates in lake sediments. Quaternary Science Reviews 87: 12-23.

MAXSON, J., and B. TIKOFF. 1996. Hit-and-run collision model for the Laramide orogeny, western United States. Geology 24: 968-972.

MCGREW, P. O., and R. SULLIVAN. 1971. The Stratigraphy and Paleontology of Bridger A. Rocky Mountain Geology 9: 66-85.

MCGREW, P. O., and M. CASILLIANO. 1975. The geologic history of Fossil Butte National Monument and Fossil Basin. National Park Service Occasional Paper Number 3: 37.

MCMAHON, T. 1973. Size and Shape in Biology. Science 179: 1201-1204.

MCMAHON, T. A., and R. E. KRONAUER. 1976. Tree Structures: Deducing the Principle of Mechanical Design. J. theor. Biol. 59: 443-466.

MCMURRAN, D. M., and S. R. MANCHESTER. 2010. Lagokarpos lacustris, A new winged fruit from the Paleogene of western North America. International Journal of Plant Sciences 171: 227-234.

MELANDRI, J. L., and N. ESPINOZA DE PERNÍA. 2009. Wood anatomy of tribe Detarieae and comparison with tribe Caesalpinieae (Leguminosae, Caesalpinioideae) in Venezuela. Revista de Biología Tropical 57: 303-319.

MERKHOFER, L., P. WILF, M. T. HAAS, R. M. KOOYMAN, L. SACK, C. SCOFFONI, and N. R. CÚNEO. 2015. Resolving Australian analogs for an Eocene Patagonian paleorainforest using leaf size and floristics. American Journal of Botany 102: 1160-1173.

METCALFE, C. R., and L. CHALK. 1950. Anatomy of the Dicotyledons. Oxford at the Clarendon Press, London.

MEYER, F. G. 1976. A revision of the genus Koelreuteria (Sapindaceae). Journal of the Arnold Arboretum 57: 129-166.

MEYER, H. W. 2007. A Review of Paleotemperature--Lapse Rate Methods for Estimating Paleoelevation from Fossil Floras. Reviews in Mineralogy & Geochemistry 66: 155-171.

MEYER, H. W., and S. R. MANCHESTER. 1997. The Oligocene Bridge Creek Flora of the John Day Formation, Oregon. University of California Press, Berkeley.

MILES, P. D., and W. B. SMITH. 2009. Specific Gravity and Other Properties of Wood and Bark for 156 Tree Species Found in North America. In Agriculture [ed.], 35 p. U.S. Forest Service, Newtown Square, PA.

601

MILLER, I. M., M. T. BRANDON, and L. J. HICKEY. 2006. Using leaf margin analysis to estimate the mid-Cretaceous (Albian) paleolatitude of the Baja BC block. Earth and Planetary Science Letters 245: 95-114.

MIN, K., R. MUNDIL, P. R. RENNE, and K. R. LUDWIG. 2000. A test for systematic errors in 40Ar/39Ar geochronology through comparison with U-Pb analysis of a 1.1-Ga rhyolite. Geochimica et Cosmochimica Acta 64: 73-98.

MOORE, P. R., J. A. WEBB, and M. E. COLLINSON. 1991. Pollen Analysis. Second ed., 216. Blackwell Scientific Publications, Inc., Cambridge.

MORRILL, C., and P. L. KOCH. 2002. Elevation or alteration? Evaluation of isotopic constraints on paleoaltitudes surrounding the Eocene Green River Basin. Geology 30: 151-154.

MORRIS, H. 2016. The structure and function of ray and axial parenchyma in seed plants. PhD diss., Ulm University, Ulm, Germany.

MORRIS, H., L. PLAVCOVÁ, P. CVECKO, E. FICHTLER, M. A. F. GILLINGHAM, H. I. MARTÍNEZ- CABRERA, D. J. MCGLINN, et al. 2016. A global analysis of parenchyma tissue fractions in secondary xylem of seed plants. New Phytologist 209: 1553-1565.

MOSBRUGGER, V. 1999. The nearest living relative method. In T. P. Jones AND N. P. Rowe [eds.], Fossil Plants and Spores: modern techniques, 261-265. Geological Society, London.

MOSBRUGGER, V., and T. UTESCHER. 1997. The coexistence approach--a method for quantitative reconstructions of Tertiary terrestrial palaeoclimate data using plant fossils. Palaeogeography, Palaeoclimatology, Palaeoecology 134: 61-86.

MULLER-LANDAU, H. C. 2004. Interspecific and Inter-site Variation in Wood Specific Gravity of Tropical Trees. Biotropica 36: 20-32.

MÜLLER-STOLL, W. R., and E. MÄDEL. 1967. Die fossilen Leguminosen-Hölzer: Eine Revision der mit Leguminosen verglichenen fossilen Hölzer und Beschreibungen älterer und neuer Arten. Palaeontographica Abt. B 119: 95-174.

MÜLLER, S., K. SALOMO, J. SALAZAR, J. NAUMANN, M. A. JARAMILLO, C. NEINHUIS, T. S. FEILD, et al. 2015. Intercontinental long-distance dispersal of Canellaceae from the New to the Old World revealed by a nuclear single copy gene and chloroplast loci. Molecular Phylogenetics and Evolution 84: 205-219.

MUNRO, S. L., and H. P. LINDER. 1997. The embryology and systematic relationships of Prionium serratum (Juncaceae: Juncales). American Journal of Botany 84: 850-860.

MURPHEY, P. C., and E. EVANOFF. 2007. Stratigraphy, fossil distribution, and depositional environments of the Upper Bridger Formation (middle Eocene), southwestern Wyoming.

602

MURPHEY, P. C., and E. EVANOFF. 2011. Paleontology and Stratigraphy of the Middle Eocene Bridger Formation, Southern Green River Basin, Wyoming, Proceedings of the 9th Conference on Fossil Resources, 83-109, Kemmerer, WY.

MURPHEY, P. C., K. E. B. TOWNSEND, A. R. FRISCIA, and E. EVANOFF. 2011. Paleontology and startigraphy of middle Eocene rock units in the Bridger and Uinta Basins, Wyoming and Utah. In J. Lee AND J. P. Evans [eds.], Geologic Field Trips to the Basin and Range, Rocky Mountains, Snake River Plain, and Terrances of the U.S. Cordillera, vol. Field Guide 21, 125-166. Geological Society of America

MURPHEY, P. C., L. L. TORICK, E. S. BRAY, R. CHANDLER, and E. EVANOFF. 2001. Taphonomy, Fauna, and Depositional Environment of the Omomys Quarry, an Unusual Accumulation from the Bridger Formation (Middle Eocene) of Southwestern Wyoming (USA) In G. F. Gunnell [ed.], Eocene biodiversity: unusual occurrences and rarely sampled habitats 361- 402. Kluwer Academic/Plenum Publishers, New York.

MURPHEY, P. C., A. LESTER, B. BOHOR, P. ROBINSON, E. EVANOFF, and E. LARSON. 1999. 40Ar/39Ar dating of volcanic ash deposits in the Bridger Formation (Middle Eocene), Southwestern Wyoming. Geological Society of America Abstracts with Programs 31: 233.

MUSTOE, G. E. 2015. Geologic History of Eocene Stonerose Fossil Beds, Republic, Washington, USA. Geosciences 5: 243-263.

MYERS, J. A. 1991. The Early Middle Eocene Torrey Flora, Del Mar, California. In P. L. Abbott AND J. A. May [eds.], Eocene Geologic History San Diego Region, vol. 68, 201-216. Pacific section SEPM, Los Angeles, CA.

NAGGAR, S. M. 2004. Pollen morphology of Egyptian Malvaceae: An assessment of taxonomic value. Turk J Bot 28: 227-240.

NEW, M., M. HULME, and P. JONES. 1999. Representing Twentieth-Century Space-Time Climate Variability. Part I: Development of a 1961-90 Mean Monthly Terrestrial Climatology. Journal of Climate 12: 829-856.

NEWBERRY, J. S. 1898. The later extinct floras of North America. United States Geological Survey, Washington, D.C., USA.

NICHOLS, D. J. 1987. Palynology of the Vermillion Creek Coal Bed and Associated Strata. In H. W. Roehler AND P. L. Martin [eds.], Geological Investigations of the Vermillion Creek Coal Bed in the Eocene Niland Tongue of the Wasatch Formation, Sweetwater County, Wyoming, 47-74. U.S. Geological Survey Professional Paper 1314-D, Washington.

NICHOLS, D. J. 2010. Reevaluation of the Holotypes of the Wodehouse pollen species from the Green River Formation (Eocene, Colorado and Utah). AASP Contributions Series 44.

603

NICHOLS, D. J., and R. F. FLEMING. 2002. Palynology and palynostratigraphy of Maastrichtian, Paleocene, and Eocene strata in the Denver Basin, Colorado. Rocky Mountain Geology 37: 135-163.

NIKLAS, K. J. 1994. Predicting the height of fossil plant remains: An allometric approach to an old problem. Am. J. Bot. 81: 1235-1242.

NORRIS, R. D., L. S. JONES, R. M. CORFIELD, and J. E. CARTLIDGE. 1996. Skiing in the Eocene Uinta Mountains? Isotopic evidence in the Green River Formation for snow melt and large mountains. Geology 24: 403-406.

OGATA, K., T. FUJII, H. ABE, and P. BAAS. 2008. Identification of the Timbers of Southeast Asia and the Western Pacific. Kaiseisha Press, Tsukuba, Japan.

OLSON, M. E., T. ANFODILLO, J. A. ROSELL, G. PETIT, A. CRIVELLARO, S. ISNARD, C. LEÓN- GÓMEZ, et al. 2014. Universal hydraulics of the flowering plants: vessel diameter scales with stem length across angiosperm lineages, habits and climates. Ecology Letters 17: 988-997.

PAN, A. D., B. F. JACOBS, J. DRANSFIELD, and W. J. BAKER. 2006. The fossil history of palms (Arecaceae) in Africa and new records from the Late Oligocene (28–27 Mya) of northwestern Ethiopia. Botanical Journal of the Linnean Society 151: 69-81.

PELL, S. K. 2004. Molecular Systematics of the Cashew Family (Anacardiaceae). PhD diss., Lousiana State Universtiy and Agricultural and Mechanical College.

PEPPE, D. J., L. J. HICKEY, I. M. MILLER, and W. A. GREEN. 2008. A Morphotype Catalogue, Floristic Analysis and Stratigraphic Description of the Aspen Shale Flora (Cretaceous– Albian) of Southwestern Wyoming. Bulletin of the Peabody Museum of Natural History 49: 181-208.

PEPPE, D. J., D. L. ROYER, P. WILF, and E. A. KOWALSKI. 2010. Quantification of large uncertainties in fossil leaf paleoaltimetry. Tectonics 29: 1-14.

PEPPE, D. J., D. L. ROYER, B. CARIGLINO, S. Y. OLIVER, S. NEWMAN, E. LEIGHT, G. ENIKOLOPOV, et al. 2011. Sensitivity of leaf size and shape to climate: global patterns and paleoclimatic applications. New Phytologist 190: 724-739.

PIGG, K. B., S. R. MANCHESTER, and M. L. DEVORE. 2008. Fruits of Icacinaceae (tribe Iodeae) from the Late Paleocene of western North America. American Journal of Botany 95: 824- 832.

PIGG, K. B., M. L. DEVORE, and K. E. VOLKMAN. 2011. Fossil Plants from Republic: A Guidebook, 86. Stonerose Interpretive Center, Republic, WA.

PIGG, K. B., R. M. DILLHOFF, M. L. DEVORE, and W. WEHR. 2007. New diversity among the Trochodendraceae from the Early/Middle Eocene Okanogan Highlands of British

604

Columbia, Canada, and northeastern Washington State, United States. International Journal of Plant Sciences 168: 521-532.

PLEDGE, N. S. 1969. Paleoenvironments and Paleoecology of part of the lower Bridger Formation, south of Opal, Wyoming. Master of Science, University of Wyoming, Laramie.

PLUMMER, M. V., and J. S. DOODY. 2010. Terrestrial Burrowing in Nesting Softshell Turtles (Apalone mutica and A. spinifera). IRCF Reptiles & Amphibians 17: 79-81.

POINAR, G. 2002. Fossil palm flowers in Dominican and Mexican amber. Botanical Journal of the Linnean Society 138: 57-61.

PRAKASH, U. 1975. Fossil woods from the Lower Siwalik Beds of Himachal Pradesh, India. The Palaeobotanist 22: 192-210.

PRASAD, V., C. A. E. STRÖMBERG, A. D. LEACHÉ, B. SAMANT, R. PATNAIK, L. TANG, D. M. MOHABEY, et al. 2011. Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae. Nature Communications 2: 1-9.

PRIGGE, B. A., and A. C. GIBSON. 2012. A Naturalist's Flora of the Santa Monica Mountains and Simi Hills, California. B.A. Prigge and A.C. Gibson, Los Angeles.

PUTZ, F. E., and P. CHAI. 1987. Ecological studies of lianas in Lambir National Park, Sarawak, Malaysia. Journal of Ecology 75: 523-531.

QUIRK, J. T., and R. B. MILLER. 1985. Vestured pits in the Tribe Cassieae Bronn (Leguminosae). IAWA Bulletin 6: 200-212.

RADTKE, M. G., K. B. PIGG, and W. WEHR. 2005. Fossil Corylopsis and Fothergilla Leaves (Hamamelidaceae) from the Lower Eocene Flora of Republic, Washington, U.S.A., and Their Evolutionary and Biogeographic Significance. Int. J. Plant Sci. 166: 347-356.

RAMOS, R. S., M. BREA, and R. PARDO. 2014. A new fossil wood of Peltophoroxylon (Leguminosae: Caesalpinioideae) from the El Palmar Formation (Late Pleistocene), Entre Ríos, Argentina. IAWA Journal 35: 199-212.

RANKIN, B. D., R. A. STOCKEY, and G. BEARD. 2008. Fruits of Icacinaceae from the Eocene Appian Way locality of Vancouver Island, British Columbia. International Journal of Plant Sciences 169: 305-314.

RASBAND, W. S. 1997-onwards. ImageJ Website http://imagej.nih.gov/ij/

READ, R. W., and L. J. HICKEY. 1972. A Revised Classification of Fossil Palm and Palm-like Leaves. Taxon 21: 129-137.

605

REES, P. M., and A. M. ZIEGLER. 1999. Paleobotanical databases and palaeoclimate signals. In T. P. Jones AND N. P. Rowe [eds.], Fossil Plants and Spores: modern techniques, 240-244. Geological Society, London.

REFULIO-RODRIGUEZ, N. F., and R. G. OLMSTEAD. 2014. Phylogeny of Lamiidae. American Journal of Botany 101: 287-299.

REID, E. M., and M. E. J. CHANDLER. 1933. The London Clay flora. British Museum (Natural History), London, United Kingdom.

REMIZOWA, M. V., D. D. SOKOLOFF, and P. J. RUDALL. 2010. Evolutionary History of the Monocot Flower. Annals of the Missouri Botanical Garden 97: 617-645.

REMIZOWA, M. V., A. N. KUZNETSOV, S. P. KUZNETSOVA, P. J. RUDALL, M. S. NURALIEV, and D. D. SOKOLOFF. 2012. Flower development and vasculature in Xyris grandis (Xyridaceae, Poales); a case study for examining petal diversity in monocot flowers with a double perianth. Botanical Journal of the Linnean Society 170: 93-111.

RENNE, P. R., C. C. SWISHER, A. L. DEINO, D. B. KARNER, T. L. OWENS, and D. J. DEPAOLO. 1998. Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating. Chemical Geology 145: 117-152.

RICH, P. M., K. HELENURM, D. KEARNS, S. R. MORSE, M. W. PALMER, and L. SHORT. 1986. Height and stem diameter relationships for dicotyledonous trees and arborescent palms of Costa Rican tropical wet forest. Bulletin of the Torrey Botanical Club 113: 241-246.

RICHTER, H. G., D. GROSSER, I. HEINZ, and P. E. GASSON. 2004. IAWA List of Microscopic Features for Softwood Identification. IAWA Journal 25: 1-70.

RIGHETTI DE ABREU, V. H., C. B. F. MENDONCA, and V. GONCALVES-ESTEVES. 2014. Pollen morphology of selected species of the subfamily Bombacoideae (Malvaceae sensu lato). Acta Botanica Brasilica 28: 352-360.

ROBINSON, P., G. F. GUNNELL, S. L. WALSH, W. C. CLYDE, J. E. STORER, R. K. STUCKY, D. J. FROEHLICH, et al. 2004. Wasatchian Through Duchesnean Biochronology. In M. O. Woodburne [ed.], Late Cretaceous and Cenozoic Mammals of North America, 391. Columbia University Press, New York.

ROEHLER, H. W. 1992a. Introduction to Greater Green River Basin Geology, Physiography, and History of Investigations. U.S. Geological Survey Professional Paper 1506-A: A1-A14.

ROEHLER, H. W. 1992b. Description and Correlation of Eocene Rocks in Stratigraphic Reference Sections for the Green River and Washakie Basins, Southwest Wyoming. U.S. Geological Survey Professional Paper 1506-D: D1-D83.

ROEHLER, H. W. 1993. Eocene Climates, Depositional Environments, and Geography, Greater Green River Basin, Wyoming, Utah, and Colorado. U.S. Geological Survey Professional Paper 1506-F: F1-F74.

606

ROSE, K. D. 2006. The Beginning of the Age of Mammals. The Johns Hopkins University Press, Baltimore.

ROWE, N., S. ISNARD, and T. SPECK. 2004. Diversity of mechanical architectures in climbing plants: An evolutionary perspective. Journal of Plant Growth Regulation 23: 108-128.

ROYER, D. L. 2012. Climate reconstruction from leaf size and shape: new developments and challenges. In L. C. Ivany AND B. T. Huber [eds.], Reconstructing Earth's Deep-Time Climate--The State of the Art in 2012, vol. 18, 195-212. The Paleontological Society.

ROYER, D. L., I. M. MILLER, D. J. PEPPE, and L. J. HICKEY. 2010. Leaf Economic Traits from Fossils Support a Weedy Habit for Early Angiosperms. American Journal of Botany 97: 438-445.

ROYER, D. L., D. J. PEPPE, E. A. WHEELER, and Ü. NINEMENTS. 2012. Roles of climate and functional traits in controlling toothed vs. untoothed leave margins. American Journal of Botany 99: 915-922.

ROYER, D. L., P. WILF, D. A. JANESKO, E. A. KOWALSKI, and D. L. DILCHER. 2005. Correlations of climate and plant ecology to leaf size and shape: potential proxies for the fossil record. American Journal of Botany 92: 1141-1151.

ROYER, D. L., L. SACK, P. WILF, C. H. LUSK, G. J. JORDAN, U. NIINEMENTS, I. J. WRIGHT, et al. 2007. Fossil leaf economics quantified: calibration, Eocene case study, and implications. Paleobiology 33: 574-589.

RYBERG, P. E., G. W. ROTHWELL, R. A. STOCKEY, J. HILTON, G. MAPES, and J. B. RIDING. 2012. Reconsidering relationships among stem and crown group Pinaceae: Oldest record of the genus Pinus from the Early Cretaceous of Yorkshire, United Kingdom. Int. J. Plant Sci. 173: 917-932.

SACK, L., C. SCOFFONI, A. D. MCKOWN, K. FROLE, M. RAWLS, J. C. HAVRAN, H. TRAN, et al. 2012. Developmentally based scaling of leaf venation architecture explains global ecological patterns. Nature Communications 3:837: 1-10.

SAKAI, A., and W. LARCHER. 1987. Frost Survival of Plants: Responses and Adaptation to Freezing Stress. Springer-Verlag, Berlin.

SALAZAR, J. 2006. Systematics of Neotropical Canellaceae. PhD diss., Cornell University, Ithaca, NY.

SALAZAR, J., and K. C. NIXON. 2008. New Discoveries in the Canellaceae in the Antilles: How Phylogeny can Support Taxonomy. Bot. Rev. 74: 103-111.

SAPORTA, G. 1878. Essai Descriptif sur les Plantes Fossiles des arkoses de Brives pres le Puy- En-Velay. Annales de la Société d’Agriculture, Science, Arts et Commerce du Puy 33: 1- 72.

607

SAVOLAINEN, V., M. W. CHASE, S. B. HOOT, C. M. MORTON, D. E. SOLTIS, C. BAYER, M. F. FAY, et al. 2000. Phylogenetics of flowering plants based upon a combined analysis of plastid atpB and rbcL gene sequences. Systematic Biology 49: 306-362.

SCHAARSCHMIDT, F. 1992. The vegetation: fossil plants as witnesses of a warm climate. In S. Schaal AND W. Ziegler [eds.], Messel: An insight into the history of life and of the Earth, 29-52. Clarendon Press, Oxford.

SCHAARSCHMIDT, F., and V. WILDE. 1986. Palmblüten und -blatter aus dem Eozän von Messel. Cour. Forsch. Inst. Senckenberg 86: 177-202.

SCHNITZER, S. A. 2005. A mechanistic explanation for global patterns of liana abundance and distribution. The American Naturalist 166: 262-276.

SCHNITZER, S. A., and F. BONGERS. 2011. Increasing liana abundance and biomass in tropical forests: emerging patterns and putative mechanisms. Ecology Letters 14: 397-406.

SEIFFERT, E. R., E. L. SIMONS, and Y. ATTIA. 2003. Fossil evidence for an ancient divergence of lorises and galagos. Nature 422: 421-424.

SEWALL, J. O., and L. C. SLOAN. 2006. Come a little bit closer: A high-resolution climate study of the early Paleogene Laramide foreland. Geology 34: 81-84.

SILVA-ROMO, G. 2010. Origen tectónico y evolución de la cuenca Tehuitzingo-Tepexi Estado de Puebla. PhD diss., Universidad Nacional Autónoma de México, Mexico City.

SIMPSON, D. A. 1995. Relationships within Cyperales. In P. J. Rudall, P. J. Cribb, D. F. Cutler, AND C. J. Humphries [eds.], Monocotyledons: systematics and evolution, vol. II, 497- 509. Royal Botanic Gardens, Kew.

SIMPSON, D. A., C. A. FURNESS, T. R. HODKINSON, A. M. MUASYA, and M. W. CHASE. 2003. Phylogenetic relationships in Cyperaceae subfamily Mapanioideae inferred from pollen and plastid DNA sequence data. American Journal of Botany 90: 1071-1086.

SINGH, V., and R. SATTLE. 1972. Floral development of Alisma triviale. Canadian Journal of Botany 50: 619-627.

SKVARLA, J. J., J. R. ROWLEY, V. C. HOLLOWELL, and W. F. CHISSOE. 2003. Annulus--pore relationship in Gramineae (Poaceae) pollen: the pore margin of Pariana. American Journal of Botany 90: 924-930.

SLEUMER, H. 1942. Icacinaceae. In A. Engler [ed.], Die natürlichen Pflanzenfamilien, vol. 20b, 322-396. Engelmann, Leipzig, Germany.

SLEUMER, H. 1980. Flacourtiaceae, 1-499. The New York Botanical Garden, New York.

SLOAN, L. C. 1994. Equable climates during the early Eocene: Significance of regional paleogeography for North American climate. Geology 22: 881-884.

608

SMITH, M. E., B. S. SINGER, and A. R. CARROLL. 2003. 40Ar/39Ar geochronology of the Eocene Green River Formation, Wyoming. GSA Bulletin 115: 549-565.

SMITH, M. E., A. R. CARROLL, and B. S. SINGER. 2008. Synoptic reconstruction of a major ancient lake system: Eocene Green River Formation, western United States. GSA Bulletin 120: 54-84.

SMITH, M. E., K. R. CHAMBERLAIN, B. S. SINGER, and A. R. CARROLL. 2010. Eocene clocks agree: Coeval 40Ar/39Ar, U-Pb, and astronomical ages from the Green River Formation. Geology 38: 527-530.

SMITH, M. E., A. R. CARROLL, J. J. SCOTT, and B. S. SINGER. 2014a. Early Eocene carbon isotope excursions and landscape destabilization at eccentricity minima: Green River Formation of Wyoming. Earth and Planetary Science Letters 403: 393-406.

SMITH, M. E., A. R. CARROLL, B. R. JICHA, E. J. CASSEL, and J. J. SCOTT. 2014b. Paleogeographic record of Eocene Farallon slab rollback beneath western North America. Geology 42: 1039-1042.

SMITH, R. Y. 2011. The Eocene Falkland Fossil Flora, OKanagan Highlands, British Columbia: Paleoclimate and Plant Community Dynamics during the Early Eocene Climatic Optimum. PhD diss., University of Saskatchewan, Saskatoon, Canada.

SMITH, R. Y., J. F. BASINGER, and D. R. GREENWOOD. 2009a. Depositional setting, fossil flora, and paleoenvironment of the Early Eocene Falkland site, Okanagan Highlands, British Columbia. Can. J. Earth Sci. 46: 811-822.

SMITH, S. Y., R. A. STOCKEY, G. W. ROTHWELL, and S. A. LITTLE. 2016. A new species of Pityostrobus (Pinaceae) from the Cretaceous of California: moving towards understanding the Cretaceous radiation of Pinaceae. Journal of Systematic Palaeontology: 1-13.

SMITH, S. Y., M. E. COLLINSON, D. A. SIMPSON, P. J. RUDALL, F. MARONE, and M. STAMPANONI. 2009b. Elucidating the affinities and habitat of ancient, widespread Cyperaceae: Volkeria messelensis gen. et sp. nov., a fossil mapanioid sedge from the Eocene of Europe. American Journal of Botany 96: 1506-1518.

SNOKE, A. W., J. R. STEIDTMANN, and S. M. ROBERTS. 1993. Geology of Wyoming. The Geological Survey of Wyoming, Laramie, WY.

SOISTER, P. E. 1968. Stratigraphy of the Wind River Formation in South-Central Wind River Basin, Wyoming. Geological Survey Professional Paper 594-A: A1-A50.

SOLTIS, D. E., P. S. SOLTIS, M. W. CHASE, M. E. MORT, D. C. ALBACH, M. ZANIS, V. SAVOLAINEN, et al. 2000. Angiosperm phylogeny inferred from 18S rDNA, rbcL, and atpB sequences. Botanical Journal of the Linnean Society 133: 381-461.

609

SOLTIS, D. E., S. A. SMITH, N. CELLINESE, K. J. WURDACK, D. C. TANK, S. F. BROCKINGTON, N. F. REFULIO-RODRIGUEZ, et al. 2011. Angiosperm phylogeny: 17 genes, 640 taxa. American Journal of Botany 98: 704-730.

SPICER, R. A. 2000. Leaf physiognomy and climate change. In S. J. Culver AND P. F. Rawson [eds.], Biotic Response to Global Change: The Last 145 Million Years, 516. Cambridge University Press, London.

SPICER, R. A. 2007. Recent and Furture Development of CLAMP: Building on th Legacy of Jack A. Wolfe. In D. M. Jarzen, S. R. Manchester, G. J. Retallack, AND S. A. Jarzen [eds.], Advances in Angiosperm Paleobotany and Paleoclimate Reconstruction Contributions Honouring David L. Dilcher and Jack A. Wolfe, vol. 258, Courier Forschungsinstitut Senckenberg, 109-118. Volker Mosbrugger, Senckenbergische Naturforschende Gesellschaft, Frankfurt am Main, Germany.

SPICER, R. A., P. J. VALDES, T. E. V. SPICER, H. J. CRAGGS, G. SRIVASTAVA, R. C. MEHROTRA, and J. YANG. 2009. New developments in CLAMP: Calibration using global gridded meteorological data. Palaeogeography, Palaeoclimatology, Palaeoecology 283: 91-98.

SPICER, R. A., S. BERA, S. DE BERA, T. E. V. SPICER, G. SRIVASTAVA, R. MEHROTRA, N. MEHROTRA, et al. 2011. Why do foliar physiognomic climate estimates sometimes differ from those observed? Insights from taphonomic information loss and a CLAMP case study from the Ganges Delta. Palaeogeography, Palaeoclimatology, Palaeoecology 302: 381-395.

STEARN, W. T. 2004. Botanical Latin. Fourth ed. Timber Press, Inc., Portland, Oregon, USA.

STEVENS, P. F. 2001 onward. Angiosperm Phylogeny Website Website http://www.mobot.org/MOBOT/research/APweb/

STOKSTAD, E. 2001. Myriad Ways to Reconstruct Past Climate. Science 292: 658-659.

STRÖMBERG, C. A. E. 2011. Evolution of Grasses and Grassland Ecosystems. Annu. Rev. Earth Planet. Sci. 39: 517-544.

STULL, G. W., and S. R. MANCHESTER. 2012. Fossils of the tribe Iodeae (Icacinaceae) from North and South America, Botany. Botanical Society of America Abstract 736, Columbus, Ohio.

STULL, G. W., R. MOORE, and S. R. MANCHESTER. 2011. Fruits of Icacinaceae from southeastern North America and their biogeographic implications. International Journal of Plant Sciences 172: 935-947.

STULL, G. W., F. HERRERA, S. R. MANCHESTER, C. JARAMILLO, and B. H. TIFFNEY. 2012. Fruits of an “Old World” tribe (Phytocreneae; Icacinaceae) from the Paleogene of North and South America. Systematic Botany 37: 784-794.

610

STULL, G. W., N. F. ADAMS, S. R. MANCHESTER, D. SYKES, and M. E. COLLINSON. 2016. Revision of Icacinaceae from the Early Eocene London Clay flora based on X-ray micro- CT. Botany 94: 713-745.

SULLIVAN, R. 1980. A Stratigraphic Evaluation of the Eocene Rocks of Southwestern Wyoming, 1-50. The Geological Survey of Wyoming, Laramie, Wyoming.

SUN, M., R. NAEEM, J.-X. SU, Z.-Y. CAO, J. G. BURLEIGH, P. S. SOLTIS, D. E. SOLTIS, et al. 2016. Phylogeny of the Rosidae: A dense sampling analysis. Journal of Systematics and Evolution 54: 363-391.

SWENSON, N. G., and B. J. ENQUIST. 2007. Ecological and evolutionary determinants of a key plant functional trait: Wood density and its communitywide variation across latitude and elevation Am. J. Bot. 94: 451-459.

TANAI, T. 1990. Euphorbiaceae and Icacinaceae from the Paleogene of Hokkaido, Japan. Bulletin of the National Science Museum. C, Geology & paleontology 16: 91-118.

TARELKIN, Y., C. DELVAUX, M. DE RIDDER, T. EL BERKANI, D. CANNIÈRE, and H. BEECKMAN. 2016. Growth-ring distinctness and boundary anatomy variability in tropical trees. IAWA Journal 37: 275-294.

TAYLOR, W. J., J. M. BARTLEY, M. W. MARTIN, J. W. GEISSMAN, J. D. WALKER, P. A. ARMSTRONG, and J. E. FRYXELL. 2000. Relationships between hinterland and foreland shortening: Sevier orogeny, central North American Cordillera. Tectonics 19: 1124-1143.

TEODORIDES, V., and Z. KVACEK. 2005. The extinct genus Chaneya Wang et Manchester in the Tertiary of Europe--a revision of Porana-like fruit remains from Öhningen and Bohemia. Review of Palaeobotany and Palynology 134: 85-103.

TERRAZAS SALGADO, T. 1994. Wood anatomy of the Anacardiaceae: Ecological and phylogenetic interpretation. PhD diss., The University of North Carolina at Chapel Hill.

TERRAZAS, T., and T. WENDT. 1995. Systematic wood anatomy of the genus Tapiria Aublet (Anacardiaceae)--a numerical approach. Brittonia 47: 109-129.

THRASHER, B. L., and L. C. SLOAN. 2009. Carbon dioxide and the early Eocene climate of western North America. Geology 37: 807-810.

THRASHER, B. L., and L. C. SLOAN. 2010. Land cover influences on the regional climate of western North America during the early Eocene. Global and Planetary Change 72: 25- 31.

TIFFNEY, B. H. 1985. The Eocene North Atlantic Land Bridge: Its importance in the Tertiary and modern phytogeography of the Northern Hemisphere. Journal of the Arnold Arboretum 66: 243-273.

611

TIFFNEY, B. H. 1999. Fossil fruit and seed flora from the Early Eocene Fisher/Sullivan site. In S. J. Johnson [ed.], Early Eocene vertebrates and plants from the Fisher/Sullivan site (Nanjemoy Formation), Stafford County, Virginia, vol. 152, 139-159. Virginia Division of Mineral Resources Publication, Charlottesville, Virginia, USA.

TIFFNEY, B. H., and E. S. BARGHOORN. 1976. Fruits and Seeds of the Brandon Lignite. I. Vitaceae. Review of Palaeobotany and Palynology 22: 169-191.

TIKOFF, B., and J. MAXSON. 2001. Lithospheric buckling of the Laramide foreland during Late Cretaceous and Paleogene, western United States. Rocky Mountain Geology 36: 13-35.

TISSERAT, B., and D. A. DEMASON. 1982. A Scanning Electron Microscope Study of Pollen of Phoenix (Arecaceae). Journal of the American Society for Horticultural Science 107: 883-887.

TRAISER, C., S. KLOTZ, U. DIETER, and V. MOSBRUGGER. 2005. Environmental signals from leaves - a physiognomic analysis of European vegetation. New Phytologist 166: 645-484.

TRAVERSE, A. 2007. Paleopalynology. Springer, Dordrecht.

TUTTLE, M. L., and M. B. GOLDHABER. 1993. Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagenetic processes in saline alkaline lakes. Geochimica et Cosmochimica Acta 57: 3023-3039.

UHL, D. 2006. Fossil plants as paleoenvironmental proxies - some remarks on selected approaches. Acta Palaeobotanica 46: 87-100.

UHL, D., and V. MOSBRUGGER. 1999. Leaf venation density as a climate and environmental proxy: a critical review and new data. Palaeogeography, Palaeoclimatology, Palaeoecology 149: 15-26.

UHL, D., S. KLOTZ, C. TRAISER, C. THIEL, T. UTESCHER, E. KOWALSKI, and D. L. DILCHER. 2007. Cenozoic paleotemperatures and leaf physiognomy—A European perspective. Palaeogeography, Palaeoclimatology, Palaeoecology 248: 24-31.

UTECH, F. H. 1992. Biology of Scoliopus (Liliaceae) I. Phytogeography and Systematics. Annals of the Missouri Botanical Garden 79: 126-142.

VINCENS, A., J.-J. TIERCELIN, and G. BUCHET. 2006. New Oligocene–early Miocene microflora from the southwestern Turkana Basin. Palaeoenvironmental implications in the northern Kenya Rift. Palaeogeography, Palaeoclimatology, Palaeoecology 239: 470-486.

VITEK, N. S. 2012. Giant fossil soft-shelled turtles of North America. Palaeontologia Electronica 15: 1-43.

612

VITEK, N. S., and W. G. JOYCE. 2015. A Review of the Fossil Record of New World Turtles of the Clade Pan-Trionychidae. Bulletin of the Peabody Museum of Natural History 56: 185-244.

WANG, X., D. C. TANK, and T. SANG. 2000. Phylogeny and Divergence Times in Pinaceae: Evidence from Three Genomes. Mol. Biol. Evol. 17: 773-781.

WANG, Y., and S. R. MANCHESTER. 2000. Chaneya, A new genus of winged fruit from the Tertiary of North America and Eastern Asia. International Journal of Plant Sciences 161: 167-178.

WEIR, G. H., and E. L. THURSTON. 1977. Scanning electron microscope identification of fossil Pinaceae pollen to species by surface morphology. Palynology 1: 157-165.

WEST, R. M. 1976. Paleontology and Geology of the Bridger Formation, southern Green River basin, southwestern Wyoming; Part 1. History of Field Work and Geological Setting Contributions in biology and geology: 1-12.

WEYLAND, H. 1937. Beiträge zur Kenntnis der rheinischen Tertiärflora. II. Erste Ergänzungen und Berichtigungen zur Flora der Blätterkohle und des Polierschiefers von Rott im Siebengebirge. Palaeontographica Abteilung B 083: 67-122.

WHEELER, E. A. 1991. Paleocene dicotyledonous trees from Big Bend National Park, Texas: Variability in wood types common in the Late Cretaceous and Early Tertiary, and ecological inferences. Am. J. Bot. 78: 658-671.

WHEELER, E. A. 2001. Fossil dicotyledonous woods from Florissant Fossil Beds National Monument, Colorado. In E. Evanoff, K. M. Gregory-Wodzicki, AND K. R. Johnson [eds.], Fossil flora and stratigraphy of the Florissant Formation, Colorado, vol. 1, 187- 203. Denver Museum of Nature & Science, Denver, CO.

WHEELER, E. A. 2011. InsideWood - a web resource for hardwood anatomy. IAWA Journal 32: 199-211.

WHEELER, E. A., and P. BAAS. 1992. Fossil wood of the Leguminosae: A case study in xylem evolution and ecological anatomy. In P. S. Herendeen AND D. L. Dilcher [eds.], Advances in Legume Systematics: Part 4. The Fossil Record, 281-301. The Royal Botanic Gardens, Kew.

WHEELER, E. A., and P. BAAS. 1993. The potentials and limitations of dicotyledonous wood anatomy for climatic reconstructions. Paleobiology 19: 487-498.

WHEELER, E. A., and S. R. MANCHESTER. 2002. Woods of the Middle Eocene Nut Beds Flora, Clarno Formation, Oregon, USA. IAWA Journal Supplement 3: 1-188.

WHEELER, E. A., and T. C. MICHALSKI. 2003. Paleocene and early Eocene woods of the Denver Basin, Colorado. Rocky Mountain Geology 38: 29-43.

613

WHEELER, E. A., R. A. SCOTT, and E. S. BARGHOORN. 1977. Fossil dicotyledonous woods from Yellowstone National Park. Journal of the Arnold Arboretum 58: 280-306.

WHEELER, E. A., R. A. SCOTT, and E. S. BARGHOORN. 1978. Fossil dicotyledonous woods from Yellowstone National Park: II. Journal of the Arnold Arboretum 59: 1-31.

WHEELER, E. A., P. BAAS, and P. GASSON. 1989. IAWA List of Microscopic Features for Hardwood Identification. IAWA Bulletin 10: 219-332.

WHEELER, E. A., M. C. WIEMANN, and J. G. FLEAGLE. 2007a. Woods from the Miocene Bakate Formation, Ethiopia: Anatomical characteristics, estimates of original specific gravity and ecological inferences. Rev. Palaeobot. Palynol. 146: 193-207.

WHEELER, E. A., P. BAAS, and S. RODGERS. 2007b. Variations in Dicot Wood Anatomy: A global analysis based on the Insidewood Database. IAWA Journal 28: 229-258.

WHITEHEAD, D. R. 1965. Pollen morphology in the Juglandaceae, II: Survey of the family. Journal of the Arnold Arboretum 46: 369-410.

WIEMANN, M. C., and G. B. WILLIAMSON. 2002. Geographic variation in wood specific gravity: Effects of latitude, temperature, and precipitation. Wood and Fiber Science 34: 96-107.

WILF, P. 1997. When are leaves good thermometers? A new case for Leaf Margin Analysis. Paleobiology 23: 373-390.

WILF, P. 2000. Late Paleocene-early Eocene climate changes in southwestern Wyoming: Paleobotanical analysis. Geological Society of America Bulletin 112: 292-307.

WILF, P., and C. C. LABANDEIRA. 1999. Response of Plant-Insect Associations to Paleocene- Eocene Warming. Science 284: 2153-2156.

WILF, P., S. L. WING, D. R. GREENWOOD, and C. L. GREENWOOD. 1998a. Using fossil leaves as paleoprecipitation indicators: An Eocene example. Geology 26: 203-206.

WILF, P., K. C. BEARD, K. S. DAVIES-VOLLUM, and J. W. NOREJKO. 1998b. Portrait of a Late Paleocene (Early Clarkforkian) Terrestrial Ecosystem: Big Multi Quarry and Associated Strata, Washakie Basin, Southwestern Wyoming. Palaios 13: 514-532.

WILF, P., C. C. LABANDEIRA, K. R. JOHNSON, P. D. COLEY, and A. D. CUTTER. 2001. Insect herbivory, plant defense, and early Cenozoic climate change. PNAS 98: 6221-6226.

WILLIAMSON, G. B., and M. WIEMANN. 2010. Measuring wood specific gravity...Correctly. American Journal of Botany 97: 519-524.

WILSON, T. K. 1960. The comparative morphology of the Canellaceae. Synopsis of genera and wood anatomy. Tropical Woods: 1-27.

614

WING, S. L. 1987. Eocene and Oligocene Floras and Vegetation of the Rocky Mountains. Annals of the Missouri Botanical Garden 74: 748-784.

WING, S. L. 1998a. Tertiary vegetation of North America as a context for mammalian evolution. In C. M. Janis, K. M. Scott, AND L. L. Jacobs [eds.], Evolution of Tertiary Mammals of North America, vol. 1, 37-65. Cambridge University Press.

WING, S. L. 1998b. Late Paleocene-Early Eocene Floral and Climatic Change in the Bighorn Basin, Wyoming. In M.-P. Aubry, S. G. Lucas, AND W. A. Berggren [eds.], Late Paleocene-Early Eocene Climatic and Biotic Events in the Marine and Terrestrial Records, 380-399. Columbia University Press, New York.

WING, S. L., and D. R. GREENWOOD. 1993. Fossils and fossil climate: the case for equable continental interiors in the Eocene. Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences 341: 243-252.

WING, S. L., and W. A. DIMICHELE. 1995. Conflict between Local and Global Changes in Plant Diversity through Geological Time. Palaios 10: 551-564.

WING, S. L., and G. L. HARRINGTON. 2001. Floral response to rapid warming in the earliest Eocene and implications for concurrent faunal change. Paleobiology 27: 539-563.

WING, S. L., and E. D. CURRANO. 2013. Plant response to a global greenhouse event 56 million years ago. American Journal of Botany 100: 1234-1254.

WING, S. L., G. J. HARRINGTON, F. A. SMITH, J. I. BLOCH, D. M. BOYER, and K. H. FREEMAN. 2005. Transient Floral Change and Rapid Global Warming at the Paleocene-Eocene Boundary. Science 310: 993-996.

WISE, W. S., and H. P. EUGSTER. 1964. Celadonite: Synthesis, thermal stability and occurrence. The American Mineralogist 49: 1031-1083.

WODEHOUSE, R. P. 1932. Tertiary pollen I. Pollen of the living representatives of the Green River flora. Bulletin of the Torrey Botanical Club 59: 313-340.

WODEHOUSE, R. P. 1933. Tertiary pollen-II The Oil Shales of the Eocene Green River Formation. Bulletin of the Torrey Botanical Club 60: 479-524.

WODEHOUSE, R. P. 1936. Pollen grains in the identification and classification of plants. VII. The Ranunculaceae. Bulletin of the Torrey Botanical Club 63: 495-514.

WOLFE, J. A. 1968. Paleogene biostratigraphy of nonmarine rocks in King County, Washington. U.S. Geological Survey Professional Paper 571.

WOLFE, J. A. 1977. Paleogene floras from the Gulf of Alaska Region. U.S. Geological Survey Professional Paper 997.

615

WOLFE, J. A. 1979. Temperature parameters of humid to mesic forests of eastern Asia and relation to forests of other regions of the northern hemisphere and Australasia. U.S. Geological Survey Professional Paper 1106: 1-37.

WOLFE, J. A. 1993. A method of obtaining climatic parameters from leaf assemblages. U.S. Geological Survey Bulletin 2040: 73 pp.

WOLFE, J. A. 1994. Tertiary climatic changes at middle latitudes of western North America. Palaeogeography, Palaeoclimatology, Palaeoecology 108: 195-205.

WOLFE, J. A., and W. WEHR. 1987. Middle Eocene Dicotyledonous Plants from Republic, Northeastern Washington. U.S. Geological Survey Bulletin 1597: 1-25.

WOLFE, J. A., and R. A. SPICER. 1999. Fossil leaf character states: a multivariate analyses. In T. P. Jones AND N. P. Rowe [eds.], Fossil Plants and Spores: modern techniques, 233-239. Geological Society, London.

WOLFE, J. A., C. E. FOREST, and P. MOLNAR. 1998. Paleobotanical evidence of Eocene and Oligocene paleoaltitudes in midlatitude western North America. GSA Bulletin 110: 664- 678.

WOOD, C. B. 1966. Stratigraphy and Paleontology of the Bridger Formation Northeast of Opal, Lincoln County, Wyoming. Master of Science, University of Wyoming, Laramie.

WRIGHT, I. J., P. B. REICH, M. WESTOBY, D. D. ACKERLY, Z. BARUCH, F. BONGERS, J. CAVENDER-BARES, et al. 2004. The worldwide leaf economics spectrum. Nature 428: 821-827.

WU, H., and Z. HU. 1997. Comparative anatomy of resin ducts of the Pinaceae. Trees 11: 135- 143.

YABE, A. 2011. Pseudotsuga tanaii Huzioka from the earliest Miocene Shichiku Flora of northeast Japan: Systematics and ecological conditions. Paleontological Research 15: 1- 11.

YAMAMOTO, T., and A. CHADWICK. 1982. Identification of Fossil Wood from the Specimen Creek Area of the Gallatin Petrified Forest, Yellowstone National Park, Montana, U.S.A., Part II. Angiosperms. J. San-iku Gakuin Junior College 11: 49-66.

YOUNG, D. A. 1972. The reproductive biology of Rhus integrifolia and Rhus ovata (Anacardiaceae). Evolution 26: 406-414.

ZETTER, R., M. WEBER, M. HESSE, and M. PINGEN. 2002. Pollen, pollenkitt, and orbicules in Craigia bronnii flower buds (Tilioideae, Malvaceae) from the Miocene of Hambach, Germany. International Journal of Plant Sciences 163: 1067-1071.

616

ZHAO, Y., and U. HERZSCHUH. 2009. Modern pollen representation of source vegetation in the Qaidam Basin and surrounding mountains, north-eastern Tibetan Plateau. Veget Hist Archaeobot 18: 245-260.

ZHENG, J., and H. I. MARTÍNEZ-CABRERA. 2013. Wood anatomical correlates with theoretical conductivity and wood density across China: evolutionary evidence of the functional differentiation of axial and radial parenchyma. Annals of Botany 112: 927-935.

ZHU, S.-D., and K.-F. CAO. 2010. Contrasting cost–benefit strategy between lianas and trees in a tropical seasonal rain forest in southwestern China. Oecologia 163: 591-599.

ZOMLEFER, W. B. 1994. Guide to Flowering Plant Families. The University of North Carolina Press, Chapel Hill, NC.

ZONNEVELD, J.-P. 1994. The Wasatchian-Bridgerian Land Mammal Age Boundary (Early to Middle Eocene) in the Desertion Point-Little Muddy Area, southwestern Green River Basin, Wyoming. Master of Science, Michigan State University, East Lansing, MI.

ZONNEVELD, J.-P., G. F. GUNNELL, and W. S. BARTELS. 2000. Early Eocene Fossil Vertebrates from the Southwestern Green River Basin, Lincoln and Uinta Counties, Wyoming. Journal of Vertebrate Paleontology 20: 369-386.

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BIOGRAPHICAL SKETCH

Sarah E. Allen, the only child of two public school teachers, grew up in the small town of

Bolton, CT and spent summers on the island of Martha's Vineyard. Her interest in the natural world appeared early as she began collecting rocks and shells, a habit which continues to this day. She was one of 64 members of the Bolton High School graduating class in 2005. While at

Hobart and William Smith Colleges (HWS) in Geneva, NY, she wrote an honors thesis in which she identified and performed a climate analysis on upper Cretaceous leaf fossils. This work was later published in a paper written with her undergraduate advisor, Nan C. Arens. Sarah earned a

BS in Geoscience, with minors in Biology and Environmental Studies from HWS in 2009 and was awarded the Donald L. Woodrow Prize in Geoscience. She spent much of the following academic year as a volunteer intern in Invertebrate Paleontology and Paleobotany at the Yale

Peabody Museum of Natural History in New Haven, CT.

In 2010, Sarah moved to Gainesville, FL to begin work on a PhD in the Department of

Biology at the University of Florida (UF) and the Florida Museum of Natural History under the guidance of advisor Steven R. Manchester. While doing her research, she worked as a lab instructor for six different courses and received the UF Department of Biology Teaching Award in 2014. Sarah also volunteered as a docent in the exhibition hall of the Florida Museum of

Natural History and blogged about her fieldwork and research on the museum website. In 2014, she received a Doctoral Dissertation Improvement Grant from the National Science Foundation.

Sarah spent several summers collecting plant fossils in the uppermost Lower Eocene Blue Rim site in the Bridger Formation in southwestern Wyoming. The leaves, wood, reproductive structures, dispersed pollen, and spore specimens from this area provide insight into the local paleoclimate and paleoecology and served as the subjects of her dissertation. She completed her

PhD in the spring of 2017.

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