AN ABSTRACT OF THE THESIS OF (Systematic Botany) Curt Gerald Carlbom for the Ph.D. in Botany (Name) (Degree) (Major') Date thesis is presented July 28, 1966 Title A BIOSYSTEMATIC STUDY OF SOME NORTH AMERICAN SPECIES OF AGROSTIS L. AND PODAGROSTIS (GRISEB.) SCRIBN. & MERR. Privacy Abstract approved Redacted for (Major professor) A taxonomic investigation was made of 24 taxa be- longing to the section Trichodium (Michx.) Trin., of Agrostis, and the genus Podagrostis. Experimental methods were employed, including: uniform garden culture of trans- plants and plants grown from seeds collected in natural populations; breeding studies; physiological and pheno- logical investigations; cytological studies; ecological studies in natural populations. Herbarium exsiccatae including the type material of most of the 24 taxa were studied. In addition, compara- the tive morphological studies were made of several of taxa in their natural habitats and again in the uniform experimental garden. Twenty -four taxa are recognized in this study. Gen- eric and species descriptions, distributional maps, gen- eric and species keys, photographs of 23 taxa including several types, and photomicrographs of meiotic and mitotic figures of 12 taxa are presented. In addition, the vari- ous taxa are discussed individually, and the criteria and concepts used for species delimitation in Agrostis and Podagrostis are presented. Chromosome counts of nine species and two varieties of Agrostis and three species of Podagrostis are reported for the first time. Additional counts of other native taxa confirm earlier published counts. Eleven of the 19 species of Agrostis are hexaploids, four species are known to be tetraploids and two species are octoploids. Two hexaploid groups have been delimited - the A. exarata and A. dieqoensis complexes. The three Podagrostis species, P. aequivalvis, P. humilis and P. thurberiana are diploids, 2n = 14. This chromosome number supports previous morphological evidence that Podagrostis is an independent evolutionary group de- serving generic status. Three Old World species of Agrostis, adventive in western North America, have been studied cytologically, and chromosome counts are presented. Agrostis perennans, hitherto unknown in western North America, was collected by the investigator on the Olympic Peninsula of Washing- ton. Putative natural hybridization and introgression were observed between several taxa of Agrostis and Podagrostis, namely: A. diegoensis and A. hallii; A. diegoensis and A. pallens; P. humilis and P. thureriana. Physiological races in P. thurberiana and A. exarata have been studied. Clinal races occur with a north -south distributional pattern in P. thurberiana. Races from southern California flowered under shorter photoperiods, while races from northern California, Oregon and Washing- ton flowered at successively later dates under increased photoperiodic regimes. Mountain ecotypes of A. exarata were obligately long -day plants, while sea -level ecotypes were day -neutral and remontant. Agrostis howellii, a species found near sea level, required a long -day photo - periodic regime and cold vernalization for floral initia- tion. Autogamy occurs in several of the native species of Agrostis. Facultative autogamy seems to occasion rapid ecotypic and racial diversification with concomitant morphological complexity within the taxa. A tentative phylogenetic scheme is presented. The North American species of Agrostis are believed to com- prise two main evolutionary groups; the "primitive" and "derived" species of section Trichodium. The "primitive" taxa are chiefly characterized by: 1) having some species with Old World distributions; 2) more northern and /or widespread distributions; 3) a perennial habit; 4) mostly medium to large anthers; 5) reproducing by allogamy; 6) having tetra -, hexa -, and octoploid chromosome levels; 7) inhabiting mesic and sylvan or bog habitats; 8) occur- ring on older geological formations and soils. The "de- rived" species are characterized by: 1) not having any conspecific taxa in the Old World; 2) more southern dis- tributions; 3) being weakly perennial or annual; 4) small anthers; 5) reproducing by autogamy or facultative auto - gamy; 6) having hexa- and octoploid chromosome levels; 7) occupying arid and semi -arid habitats; 8) occurring on newer geological formations and soils. A BIOSYSTEMATIC STUDY OF SOME NORTH AMERICAN SPECIES OF AGROSTIS L. AND PODAGROSTIS (GRISEB.) SCRIBN. & MERR. by CURT GERALD CARLBOM A THESIS submitted to OREGON STATE UNIVERSITY in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY June 1967 APPROVED: Redacted for Privacy Professor of Botany In Charge of Major Redacted for Privacy Chairman of the Depa4tment of Botany Redacted for Privacy Dean of Graduaté `School Date thesis is presented ` ______ y / 76 Typed by Trudie Vallier ACKNOWLEDGEMENTS To Dr. Kenton L. Chambers, Professor of Botany and Curator of the Oregon State University Herbarium, the author would like to express his deepest gratitude for the counsel, encouragement and many helpful suggestions that he has provided during the course of the investiga- tion and in the preparation of the thesis. The author expresses special thanks to Dr. Roy A. Young, former Chairman of the Department of Botany, for providing the assistantship and instructorship in botany. Appreciation is conveyed to the author's colleagues in taxonomy: Mrs. LaRea Johnston, Dr. Milton Dean, Mr. James Estes and Mr. Harold Lint for assistance in many ways, and to Miss Georgia Mason, Mr. Steven Ebert and Dr. Chris Kjeldsen for contributing seeds of native species of Agrostis. The author is especially grateful to Mrs. Willeta Smith, Herbarium Technician and friend, for much assistance. Appreciation is due Dr. Beecher Crampton for supply- ing seeds and voucher specimens of several native Califor- nia species of Agrostis, and to Dr. Bonita Neiland for making available cytological materials of Agrostis and Podagrostis species from Alaska. The author acknowledges Dr. Knut Faegri for his helpful suggestions and for pro- viding the transplant of Podagrostis humilis. Special acknowledgement is conveyed to Drs. Arthur Cronquist, Eric Hultén, Robert Hoover, John Thomas Howell, C. Leo Hitchcock, Marion Ownbey, Thomas Soderstrom and G. Ledyard Stebbins, Jr., all of whom have assisted the study in some way - providing herbarium specimens, seeds, professional knowledge of certain taxa, etc. Finally, the author would like to express his ap- preciation and thanks to his wife, Ulla, who has provided constant encouragement and inspiration. TABLE OF CONTENTS Page I. INTRODUCTION 1 II. LITERATURE REVIEW 3 General Taxonomic and Monographic Studies 3 Taxonomic Treatments of North American Agrostis and Podagrostis 7 Ecology 10 Cytology 11 Economic Importance of Agrostis 14 Physiological and Phenological Character- istics 15 III. MATERIALS AND METHODS 17 Transplants and Seed Collections 17 Cultivation Procedures 21 Hybridization Procedures 21 Determination of Pollen Viability 22 Preparation of Cytological Materials 24 Slide Preparation 26 IV. DISCUSSION 28 Uniform Garden Studies 28 Ecological Races 28 Genotypic Responses and Phenotypic Modifiability 31 Light and Temperature Responses 31 Floral Biology 32 Selfing and Self -Compatibility Studies 33 Cytology 36 Cytology of Podagrostis 44 Evolution and Phylogeny 46 V. TAXONOMY 59 Introduction 59 Species Delimitation 62 Genus Description of Agrostis L. 62 History of the Genus Agrostis L. 64 Key to the Genera Agrostis L. and Podagros- tis (Griseb.) Scribn. & Merr. 65 Key to the Species of Agrostis L. 66 Agrostis aristiglumis Swallen 73 Agrostis blasdalei Hitchc. 77 Agrostis densiflora Vasey 82 TABLE OF CONTENTS (Continued) Page, Agrostis diegoensis Vasey 89 Agrostis exarata Trin. var. exarata 102 Agrostis exarata Trin. var. ampia (Hitchc.) Hitchc. 114 Agrostis exigua Thurb. 119 Agrostis hallii Vasey 122 Agrostis hendersonii Hitchc. 129 Agrostis hooveri Swallen 131 Agrostis howellii Scribn. 133 Agrostis idahoensis Nash 137 Agrostis lepida Hitchc. 143 Agrostis longiligula Hitchc. 145 Agrostis microphylla Steud. 149 Agrostis oregonensis Vasey 155 Agrostis pallens Trin. 160 Agrostis perennans (Walt.) Tuckerm. 164 Agrostis scabra Willd. var. scabra 169 Agrostis scabra Willd. var. qeminata (Trin.) Swallen 178 Agrostis variabilis Rydb. 182 Genus Description of Podagrostis (Griseb.) Scribn. & Merr. 190 History of the Genus Podagrostis (Griseb.) Scribn. & Merr. 191 Key to the Species of Podagrostis ( Griseb.) Scribn. & Merr. 192 Podagrostis aequivalvis (Trin.) Scribn. & Merr. 192 Podagrostis humilis (Vasey) Björkm. 197 Podagrostis thurberiana (Hitchc.) Hultén 202 SUMMARY 211 BIBLIOGRAPHY 216 LIST OF FIGURES Figure Page 1 Photomicrographs of chromosomes of species of Agrostis and Podagrostis 42 2 Photographs of species of Agrostis 43 3 Photographs of holotypes of Agrostis 45 4 Diagram of putative phylogenetic relation- ships of the North American species of Agrostis and Podagrostis 50 5 Distributional map of Agrostis aristiglumis Swallen, Agrostis blasdalei Hitchc., Agros- tis exigua Thurb., Agrostis hooveri Swallen and Agrostis lepida Hitchc. 75 6 Photographs of holotypes of Agrostis 76 7 Photographs of species of Agrostis 79 8 Illustrations of lemmas and paleas of selected species of Agrostis and Poda- grostis 81 9 Distributional map of Agrostis densiflora Vasey 84 10 Photographs of species of Agrostis, Pod- agrostis and Polypogon cultivated in the uniform experimental garden 86 11 Photographs of