During the half century following initial observations by these early explorers, many botanists carefully col- 

 lected specimens in the Intermountain region. Alice Eastwood of the California Academy of Science studied the flora 

 of southern Utah in the latter years of the 19th century and later returned for many extensive trips with her associate 

 J. T. Howell. E. L. Greene carefully collected in the Intermountain region during this period. A. A. Heller and 

 P. B. Kennedy of Nevada collected in Utah during the early 1900's. Aven Nelson and F. Macbride of Wyoming studied 

 the northern areas of the Intermountain region . 



M. E. Jones, the first student of the entire Intermountain flora, is most often remembered for his cutting 

 criticism of all the other botanists . His work on Astragalus is still highly respected, as is his work on many other 

 groups . 



Nine books on the flora of various parts of the Intermountain region have been published since 1900. Aven 

 Nelson (1909) revised Coulter's old manual (1885) of the central Rocky Mountains. P. A. Rydberg (1917) published 

 a large manual of the Rocky Mountain flora. Ivar Tidestrom (1925) published the only manual that covers most of the 

 region. A. O. Garrett published several floras on the spring flowers of Utah during the 1920's. Five manuals have 

 been written recently. Morton E. Peck and R. J. Davis have written manuals on the flora of Oregon and Idaho, respec- 

 tively. A. H. Holmgren has published two handbooks, one on the flora of northeastern Nevada and another treating 

 the northern Wasatch region of Utah. Stanley L. Welsh, Michael Treshow, and Glen Moore published a guide to 

 common Utah plants in 1964. 



The "hard to get" places became more accessible as dependable transportation became available in the 1930's. 

 Such botanists as W . P. Cottam, Percy Train, H. L. Mason, P. A. Munz, B. F. Harrison, Bassett Maguire, J. T. 

 Howell, R. J. Davis, D. D. Keck, A. H. Holmgren, K. H. Beach, and A. J. Cronquist have made important 

 contributions to the known flora of the region. 



Special note should be made of four botanists who have collected widely in the Intermountain region since the 

 1930's. Their numerous collections have aided in the writing of this checklist. Bassett Maguire, curator of the 

 Intermountain Herbarium from 1931 to 1942, is now head curator of the New York Botanical Garden. 



Arthur H. Holmgren, the present curator of the Intermountain Herbarium, was a student of Bassett Maguire 

 and collected for several years with him. Holmgren has published HANDBOOK OF THE VASCULAR PLANTS OF 

 THE NORTHERN WASATCH and HANDBOOK OF THE VASCULAR PLANTS OF NORTHEASTERN NEVADA. 



Rupert C . Barneby deserves special recognition for his careful survey of the Intermountain region during the 

 past 25 years. His numerous publications have increased the number of known species of this region. Barneby's 

 scholarly publications on the genus Astragalus are a most important contribution. He has described numerous 

 endemic plants from Utah and Nevada, and has published many notes on plant distribution. 



Arthur J. Cronquist, curator of the New York Botanical Garden, has in the last few years become a serious 

 student of the Intermountain flora. Cronquist, with C. L. Hitchcock and others, is writing a flora of the Pacific 

 Northwest. He and A. H. Holmgren have planned collaboration in publishing ILLUSTRATED FLORA OF THE 

 INTERMOUNTAIN REGION. 



Stanley L. Welsh, Brigham Young University, has collected many interesting plants in some of the most remote 

 areas of Utah. 



Noel H. Holmgren and James L. Reveal are among the most recent botanists to make extensive collections in 

 the Intermountain region. 



ORGANIZATION OF THIS CHECKLIST 



The concept of the species and other taxa 1 in this checklist is conservative. Although a checklist is not 

 floristic in nature, several comments have been included in the text that ordinarily would be omitted from such a 

 study. A. S. Hitchcock's MANUAL OF GRASSES OF THE UNITED STATES and Elbert L. Little's CHECKLIST 

 OF NATIVE AND NATURALIZED TREES OF THE UNITED STATES have been followed unless recent monographs 

 show that changes in nomenclature should be made . 



Nearly all the families are arranged in a phylogenetic order, following the Engler and Prantl system. Genera 

 and species are arranged alphabetically. Synonymy follows its accepted taxon in alphabetical order. 



Taxon (pi. taxa). A general term applied to any taxonomic element, population, or group, irrespective 

 of its classification level. 



iv 



