INTRODUCTION 



PRELIMINARY WORK 



In 1890, the author spent a month in western Nebraska. In the following 

 summer he was commissioned to collect in the same region for the United States 

 Department of Agriculture, and in 1892 in the Black Hills of South Dakota. A 

 report on the last was published in 1896, in the CONTRIBUTIONS FROM THE NA- 

 TIONAL HERBARIUM, volume 3. These trips first introduced him to the flora of 

 a part of the region covered by this manual. Since then he has done field work, 

 partly for the United States Department of Agriculture and partly for the New 

 York Botanical Garden, in Montana, Yellowstone National Park, Colorado and 

 Utah, and has made shorter stops in eastern Idaho and southern Wyoming. In 

 all, he has spent eleven summers in the Rocky Mountain region. In this field 

 work he was associated with or assisted by the following men: C. L. Shear, 

 Ernst A. Bessey, A. O. Garrett, J. H. Flodman, F. K. Vreeland, and E. C. Carl- 

 ton, to whom thanks are due. 



After collecting for two summers and a half in Montana and the Yellowstone 

 National Park, the author published in 1900, a CATALOGUE OF THE FLORA OF 

 MONTANA AND THE YELLOWSTONE NATIONAL PARK.* In preparing this, he 

 studied the extensive collections made by Frank Tweedy of the United States 

 Geological Survey, as well as that of W. M. Canby, and one made for the World's 

 Fair in Chicago, 1893. 



In 1901 the author was requested to determine the collection accumulated at 

 the Agricultural College at Fort Collins, Colorado, made by James Cassidy, C. 

 S. Crandall, J. H. Cowan, and their assistants and students, and finally to pre- 

 pare the results for publication. THE FLORA OF COLORADO f appeared in 1906. 

 At this time the author had spent a summer and a half collecting in Colorado and 

 the New York Botanical Garden had secured an almost complete set of C. F. 

 Baker's, and Baker, Earle and Tracy's collections in that state. Together with 

 the older collections preserved in the herbarium of Columbia University the 

 material mentioned above made possible an almost complete catalogue of the 

 Colorado flora. 



The preparation of the manual has taken a longer time than expected, as 

 only a small part of the author's time could be used for the work. During the 

 time (1900-1916) the work has been progressing, the author has published a 

 series of 29 papers under the title "Studies on the Rocky Mountain Flora," in 

 which numerous new species have been published. The publication of a second 

 edition of Coulter's Manual in the form of "A New Manual of Botany of the 

 Central Rocky Mountains," by J. M. Coulter and Aven Nelson, in 1909, made 

 the appearance of the contemplated flora less urgent, as the need was partly 

 supplied, and the issuing of the manual was delayed. 



MATERIAL USED IN THE WORK 



The main part of the work has been done in the herbarium of the New York 

 Botanical Garden, where also the collections of Columbia University (including 

 the Torrey and Morong herbaria) are deposited. These herbaria contain numer- 

 ous types or duplicates of types of species described by Torrej^, Torrey and Gray, 

 Nuttall, Hooker, and Richardson, as well as the first sets of several collections 

 and duplicate sets of many others. 



The author has visited the United States National Herbarium five times, 

 for weeks at a time, and has often had specimens as loans for study. He has 

 gone through it quite thoroughly, except the family CICHORIACEAE. The studies 



* Mem. N. Y. Bot. Gard. vol. 1. 



t Agr. Exp. Sta. Colo. Agr. Coll. Bull. no. 100. 



