Please do not destroy or throw away this publication. If you have no further use for it write to the Geological Survey at Washington and ask for a frank to return it UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary GEOLOGICAL SURVEY W. C. Mendenhall, Director Professional Paper 185-C THE .RECOGNIZABLE SPECIES OF THE GREEN RIVER FLORA BY ROLAND W. BROWN Shorter contributions to general geology, 1934-35 (Pages 45-77) a ~--~A UNITED STATES GOVERNMENT'PRINTING OFFICE WASHINGTON : 1934 For sale by the Superintendent of Documents, Washington, I).C. - - - - - - Price 10 cents metadc957809 CONTENTS Page A bb s t r a .. ..-- - - - - - - -..- - - - - - -.- --..- - - - - - - - - - - - - - - - - - - - - - - - --..-- - - - - - - --..--.-..-..-.-.- --..- - - - - - -..-..- -..-- - - - - - - - - - .. ..-- -_ - -_44 Introduction. _ __. ...---------------------------------------------------------------------------------------- 45 Synonyms, changes of name, and rejections.--------------------------------------------------------------------46 The recognizable species of the Green River flora------------------------------------------------------------- 47 The significant species of the flora._ ....------------------------------------------------------------------------ 49 Systematic descriptions_--- ..-------------------------------------------------------------------------------- 51 ILLUSTRATIONS Page PLATES 8-15. Fossil plants from the Green River formation. ..---------------------------------------------------- 69 II THE RECOGNIZABLE SPECIES OF THE GREEN RIVER FLORA By ROLAND W. BROWN ABSTRACT same locality as other species which he did include. The identification of new collections of fossil plants from No doubt these species were overlooked because they the Green River formation of middle Eocene age made it nec- had been stored among other scattered collections. essary to reexamine the megascopic types of the Green River With the addition of these strays, the transfer of flora. This study resulted in the reassignment of some species some species to their proper synonymy, and the exclu- and the rejection of such species as were based on fragmen- tary, indefinable specimens. The recent collections yielded sion of ill-defined or unrecognizable forms, the Green 22 new species. Exclusive of the microscopic forms of thallo- River floral list now presents a body of fairly well phytes and pollens, the flora now numbers 135 megascopic characterized species. Though some of the species in species that are considered to be recognizable and distinctive. this list may not be correctly allocated botanically, it The new elements found in the flora do not alter the previously expressed opinion that the megascopic Green River flora lived is hoped that they have been segregated so distinctly in a warm-temperate well-watered environment. as to be clearly recognizable and therefore practically useful in making future identifications. INTRODUCTION Our knowledge of the Green River flora is prob- The middle Eocene Green River shales of western ably still meager in comparison to what it may be Colorado, eastern Utah, and southwestern Wyoming eventually. At the test pits of oil-shale prospectors continue to yield new fossil material that enlarges our in all parts of the region where the formation crops knowledge of the Green River flora and tends to clar- out there doubtless exist plant remains which await ify our notions of the general environmental situation discovery and collection. of the Green River lakes. The plants described in this The Green River flora is definitely of middle Eo- paper are largely contained in recent collections or cene age, because the deposits in which it occurs lie acquisitions by persons or institutions not connected stratigraphically above the Wasatcli formation and with the United States Geological Survey, through below the Bridger formation. This flora, therefore, whose courtesy I was permitted to examine the collec- has some importance as a standard of comparison in tions and to describe such species as may be new to the discussion of the geologic age and the biologic science. Grateful acknowledgment for these favors relations of floras which )rece(led or followed it in is hereby made to Prof. T. D. A. Cockerell and Prof. the same or adjoining regions. The Fort Union and Junius Henderson, of the University of Colorado; Dr. Florissant floras are two in which particular interest Ira Edwards, of the Milwaukee Public Museum; Prof. centers; but before adequate comparisons can be made 0. M. Ball, of the Agricultural and Mechanical Col- with these floras they must be restudied and revised. lege of Texas; and the late Dr. Arthur Hollick, of the The Fort Union flora is clearly older than the Green New York Botanical Garden. River flora, because it occurs in beds that lie beneath For a few days during the field season of 1930 I the Wasatch, which in turn lies beneath the Green accompanied W. H. Bradley, of the Geological Survey, River formation. On the other hand, it is not so on a visit to outcrops of the Green River formation in clear that the Florissant flora is as much younger southwestern Wyoming. We made small collections of than the Green River as has been supposed. Placed fossil plants near the classic fossil fish localities at in parallel columns, the identical or nearly identical Fossil and Green River, Wyo. These as well as all the species common to both floras are as follows collections mentioned above came from the upper part Green River Florissant of the Green River formation. O'ul~lluS xwilnnttae--------------_ P( ) )u Ius l)yrifolia Salix cockerell___ Salix florissanti During the process of identifying the specimens Myrica minuta--------------- Myrica (Irymeja in the new collections I reexamined the types of the Juglans crossii----------------- Juglans magnifica Green River fossil flora in the United States National Hicoria juglandiformis------- H-icoria juglandiformnis Museum. This study resulted in the discovery that Quercus drymeja--------------- Quercus drymeja (eltis mccoshii some species not originally included in the flora by Celtis mccoshii__ Lomatia coloradensis_ Lomatia terminalis Knowlton 1 had the same matrix and were from the Lomatia acutiloba___-- -______ Loinatia acutiloba 1 Knowlton, F. H., Revision of the flora of the Green River forma- Banksites lineatulus--__-__--__-__- Banksites lineatus tion : U.S. Geol. Survey Prof. Paper 131, pp. 133-182, 1923. Odostemon eocenia--------------- Odostenion fl orissan tensis 45 46 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1934-35 Green River Florissant SYNONYMS, CHANGES OF NAME, AND REJECTIONS Liquidambar callarche_______.____Liquidambar convexum Amygdalus gracilis_______________Amygdalus gracilis The restudy of the type specimens of the Green Mimosites coloradensis____________Mimosites linearis River flora in the light of new material included in a Cassia hesperia------------------ Cytisus florissantianus few large collections makes the following changes Pbdogonium americanuni__________Podogonium acuininatuin necessary. The reasons for the changes, Ailanthus lesquereuxi_____________Ailanthus americana unless given Ihus variabilis__._________________Ithus coriaroides immediately, are fully stated in the systematic de- Sapindus dentoni________________Sapindus coloradensis scriptions of the several species. Koelreuteria viridifluniinis_-____-__Koelreuteria alleni Acer lesquereuxii Knowlton. Seed=Acer mysticum Kirchner. Ilex coloradensis-----------------__ Ilex leonis Ailanthus longepetiolata Lesquereux. Leaf=Rhus longepeti- P'arthenocissus tertiaria__________- Parthenocissus osborni olata (Lesquereux) Brown, n. comb. Seed=Ailanthus les- Tilia scudderi_______.___________Tilia populifolia quereuxi Cockerell. Sterculia coloradensis------------ Sterculia engleri Alnus kefersteinii (Goeppert) Unger. Lesquereux, U.S. Geol. Fraxinus flexifolia________________ Fraxinus miespilifolia Survey Terr. Rept., vol. 7, p. 140, p1. 64, fig. 11, 1878= Apc(ynophyllum wilcoxeise____.___Apocynophyllum pealii 1'iburnum asperum Newberry. Sambucus? winchesteri____________ Sambucus ellisine Banisteria bradleyi Brown=Cassia hesperia Brown. It would appear, therefore, from their commonalty Banksia: cockerelli Brown=Salix longiacuminata Knowlton. (If species and general composition, together with their Betula cocenica Brown=Betula coloradea Brown, n. name. H umelia coloradensis Cockerell=Leyuminosites lesquereuxiana relative geographic contiguity. that these two floras Knowlton. were closely related biologically. That they may have Caenom yces cucalpytae Knowlton=Sphaerites, species of. been separated by a considerable time interval is pos- Caenom yccs planerae Brown=Sphaerites, species of. sib'e but in my. opinion is not definitely established. Caenomyces sapindicola Knowlton=Sphaerites, species of. Carpolithus capsularis Brown=Carpites viburni Lesquereux. A flora closely related to and of the same or ap- Carpolithus ellipticus Brown=Carpolithus prunoides Brown, proximately the same age as the Green River flora n. name. is that described by Berry - from the Wind River Celtis debequensis Brown=Celtis rccoshii Lesquereux. Basin of Wyoming. in which he finds 21 species com- Cinnamomnum scheuceleri Heer. Lesquereux, U.S. Geol. Sur- mon to the two floras. Berry 3 has also recently de- vey Terr. Rept., vol. 8, p. 38, fig. 6, 1883=Ficus wyomingiana Lesquereux. scribed a few small collections from localities in Wyo- Cissus parrottiaefolia Lesquereux. See Knowlton, U.S. Geol. ming at horizons