Brigham Young University BYU ScholarsArchive Theses and Dissertations 1973-04-01 Distribution and relationships of Utah brome grasses in western North America Jerry B. Anderson Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd BYU ScholarsArchive Citation Anderson, Jerry B., "Distribution and relationships of Utah brome grasses in western North America" (1973). Theses and Dissertations. 8012. https://scholarsarchive.byu.edu/etd/8012 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. DISTRIBUTIONAND RELATIONSHIPS OF UTAHBROME GRASSES IN WESTERNNORTH AMERICA A Thesis Presented to the Department of Botany and Range Science Brigham Young University In Partial Fulfillment of the Requirements for the Degree Master of Science by Jerry B. Anderson April 19'i3 ii This thesis by Jerry B. Anderson is accepted in its present form by the Department of Botany and Range Science ·of Brigham Young University as satisfying the thesis requirement for the degree of Master of Science. iii ACKNOWLEDGMENTS Grateful acknowledgment is made for the valuable suggestions and assistance given by the chairman of my advisory committee, Dr. Stanley Welsh, and to Dr. Wilmer W. Tanner, the other member of my graduate committee. Appreciation is extended to Dr. Walter P. Cottam, without whose encouragement I would never have entered the field of Botany. Special thanks are due the curators of the many herbaria of the Intermountain Region for making specimens available for study. Thanks also to Larry C. Higgins who drew and furnished copies of the map of Utah. To my wife, LaPrele, deepest appreciation is expressed for her untiring devotion, patient help for these several years, and cooperation. She also assisted in the preparation of the drawings. TABLEOF CONTENTS Page ACKNOWLEDGEMENTS . iii f· LIST OF TABLES V LIST OF FIGURES . vi INTRODUCTION 1 MATERIALSAND METHODS . 2 Historical account 3 Distribution and ecology 5 General morphology 6 Cytology and generic relations 8 TAXONOMICTREATMENT_. 15 LIST OF REFERENCES . 72 APPENDIX-Index of Synonyms 81 V LIST OF TABLES Table Page 1. Nomenclature and historical development of the genus and sub generic taxa in Bromus . 7 2. Sub-families and Tribes of the Family Gramineae 11 3. Chromosome numbers reported for Utah Bromus 13 vi LIST OF FIGURES F_igures Page 1. Illustration of Bromus marginatus .. 26 2. Illustration of Brornus willdenowii 30 3. to 6. Maps of distribution for Bromus marginatus, B. marginatus var. polyanthus, ~- willdenowii, and B. 1.nermis . • . • . 32 7. Illustrations of Bromus carinatus, B. porteri, and B. trinii . .- . 38 8. Illustration of Bromus canadensis 41 9. Illustration of Bromus vulgaris 44 10. to 13. Maps of distribution for Brcmus porteri, ~- canadensis, ~-· j aponicus, and B. commutat:us 48 14. Illustrations of Bromus commutatus and B. japonicus so 15. Illustration of Bromus hrizaeforr.tis ... 56 16. to 19. Maps of distribution for Bromus racemos 1.1s, ~- mollis, B. brizaeformis, and~- trinii .. 58 20. Illustrations of Bromus tectorum and B. rubens 62 21. Illustration of Bromus sterilis 66 22. to 25. Maps of distribution for Bromus tectorum, B. sterilis, .Q_.rub~~~-., and B. dianarus .... 68 1 INTRODUCTION Since the revision of Bromus by Shear (1900) and publication of the Manual of Grasses of the United States (Hitchcock, 1935) a consider- able amount of new study material has become available. Wagnon (1952) did a revision of one of the five sections, and there have been some cytological studies of parts of the genus. There has been a variety of treatments by a number of authors, and some disagreement in interpretation of entities. Specific and generic delimitations have varied from one author to another with a resulting proliferation of name proposals. Bromus has continued to be a problem genus in Utah, and there has been a need for a comprehensive study. This study is an investigation of the taxonomy and biogeography of Bromus in Utah. In gen~-ral the treatment is concerned with plants at the species level, but some infraspecific taxa have been included. I have attempted to present a useful definition of the species within the genus for those concerned with problems of classification in Utah. In some aspects it is preliminary since detailed and lengthy investiga- tions of individual species and s-pecies complexes will be required for definitive solution to a number of problems. The problems concerning nomenclature of the entities involved in this study have been partially solved by previous authors (Stapf, 1928; Hitchcock, 1935; Wagnon, 1952) and I have adocted their work as a basis for my nomcnclatural treatment. 2 MATERIALSAND METHODS The materials used in this study are largely the dried and pressed specimens in herbarium collections. Over 1000 specimens were carefully examined to provide accurate and consistent descriptions of ,t the taxa, to obtain information on habitat and other useful data, and to determine distribution and variability in the constituent groups. Because of the large number of specimens examined, citation of all of them has not been attempted. The original descriptions of our species were examined with illustrations and commentaries concerning the type specimens wherever possible. Lack of time and funds precluded any first-hand study of the type specimens, most of which are available only in Europe. Taxonomic criteria relating to size, length, and shape were evaluated through measurements of plant structures with the aid of low- power binocular microscopes and a 15 cm, ruler graduate~ in millimeters. Herbaria from which spedmens have been seen, with the standard abbreviations (Lanjow & Stafleu, 1964) by which they are referred to in the text are as follows: ASC Arizona State College, Fl2.gsta.ff, Arizona. BRY Brighar.1 Young University, Provo. Utah. CCH Colorado College, Pueblo, Colorado. DAV University o_f California, Davis California. DIX Dixie Junior College, St. George, Utah DS Dudley Herbarium, Univ. of California, Berkeley, Calif. ISC Iowa State College, Alnes, Iowa. 3 JEPS .Jepson Herbarium, Univ. of Calif., Berkeley, Calif. MIN . University of Minnesota, Minneapolis, Minnesota. NCU University of North Carolina, Chapel Hill, N. Carolina. NY New York Botanical Garden, New York; New York. OKLA Oklahoma State University, Stillwater, Oklahoma. RIK Rick's College, Rexburg, Idaho. RM Rocky Mountain Herbarium, Univ. of Wyoming, Laramie, Wyo. SLP Slippery Rock State College, Slippery Rock, Penn. SUSC Southern Utah State College, Cedar City, Utah. UC University of California, Berkeley, Califor·nia. UC! University of California, Irvine, California. UT University of Utah, Salt Lake City, Utah. UTC Intermountain Herbarium, Utah State University, Logan, Ut. USFS Forest Service Herbarium, U.S. Dept. of Agriculture. WES Weber State College, Ogden, Utah. WTS West Texas State University, Canyon, Texas. Historical Account The modern origin of the name Brom~ is revealed by Linneaus in his Philosophia Br::itani~a (1751:188). Bromus was derived from the ancient Greek word ~pwµ.a:meaning food, and from that w:ird also comes the name l3rot"-oi;meaning ,: oat". Linneaus indicates that Theophrastus and Dioscorides used the latter term. It appears that Linneaus was the first modern author to apply the name as currently used, but he does cite the earlier works of •Monti and Scheuchzer as showing representa-- tives of Bromus on various plates of their separate works. 4 Professor S.M. Tracy at the AMS meeting ln 1893 reported on the distribution of the 20 species known in the United States at that time, and noted that half of the number were innnigrants (Beal, 1896:668). Shear (1900) describes 40 species and 20 yarieties, while 42 species and 12 varieties are listed for the United States in Hitchcock's manual (1951). Shear listed 18 species as indigenous, and Hitchcock's manual recognizes 22. A compilation of the species in the Genus, as at present recognized in the wider sense throughout the world, would yield a total probably just short of 100. The first revisionary treatment of Bromus was that of Shear (1900). He treated the North American species occurring North of Mexico. A very significant stride forward in agrostology crune with the publica- tion of Hitchcock's (1935) Manual of Grasses of the United States. The publication of this manual has given a degree of confidence to students of the grass family, and herbarium collections and the number of re- search papers on grasses h;ive increased enormously since the advent of that treatment. Both Shear (!900) and Hitchcock (1935) accepted Bromus secalinus as the type of the genus on the l:,asis of its being the first species listed in the first edition of Species Plantarum of Linneaus (1753). Wagnon (1952) in his revision of the section Bromopsis argues that B. arvensis is the type of the genus. The controversy has been a factor leadirtg to the acceptance of the concept of a "standard" species for Bromus. Stapf '(1928), Hitchcock (1935), and i'!agnon (1952) all accept B. sterilis as the standard species, that is, the species that best represents the taxonomist's concept of a brome grass. Stapf (1928) reviewed the nomenclature of B-ro:r.usand presented a table in his work that shows the historical development of the concept 5 of the genus from. 1737 to 1913. It points out the trend that has de- veloped since the work of Parlatore in 1844, to replace Linneaus' B. secalinus and its allies with the B. sterilis group as the true Bromi. Some authors entirely eliminated the B. secalinus group from the genus, but since about 1935 there has come to be an increasing amount of evidence that the genus as it is now recognized in its wider sense is probably a valid natural grouping.