vi INTRODUCTION 



there included investigations of the types of species described by Vasey, Coville, 

 Rose, Hitchcock, Scribner, Standley, and others; Dr. E. L. Greene's herbarium 

 was deposited there at that time. The author has also made four similar visits 

 to the Gray Herbarium, mainly to study types, especially those of plants de- 

 si Tibed by Gray, Watson, Robinson, Fernald, Greenman, and others; three 

 short visits to the Philadelphia Academy to study the types of Pursh and Nut-tall; 

 one to the Field Museum, Chicago; one to the Missouri Botanical Garden; one 

 to the Geological Survey of Canada; and a day's stop at the Rocky Mountain 

 Herbarium at Laramie. In 1901 he spent more than a week at the Royal Gar- 

 dens, Kew, where he studied all the types of the plants described in Hooker's 

 FLORA BOREALI-AMERICANA, and made a visit to the British Museum, which con- 

 tains many of Nuttall's types. The herbarium of the College of Pharmacy of 

 New York City has often been consulted and specimens borrowed therefrom. 

 In addition, the following herbaria have passed through his hands for study and 

 determination: Herbarium of the Agricultural College of Colorado; Herbarium 

 of the Agricultural College of Montana (before 1900) ; Frank Tweedy's herbarium, 

 now at Yale University; and the herbaria of F. D. Kelsey and F. E. Leonard, now at 

 Oberlin College. The only important collections from the Rocky Mountains 

 not studied are that of M. E. Jones and that of the University of Wyoming; 

 many duplicates from these have been available, however. The author has also 

 corresponded for years with Mr. Osterhout, Prof. Garrett, Prof. Cockerell, Mr. 

 Macoun, and many others. 



AREA COVERED BY THE MANUAL 



When the manual was first contemplated the author estimated that it would 

 comprise the description of about 4000 species; this estimate might have proved 

 correct if the work had been limited to the Rocky Mountains themselves. His 

 knowledge of the vegetation of the plains east of them, a flora not adequately 

 treated in any manual, induced the author to include that also. As he has been 

 interested in the flora of the northern Rockies, perhaps more than any one else 

 in the United States, the Geological Survey of Canada has for years sent the first 

 set of its exchanges from the Rocky Mountain region to the New York Botanical 

 Garden; it was desirable, therefore, to include the flora of this part of Canada in 

 the manual, and perhaps 200 northern species have been added. The parts of 

 Utah west and south of Wahsatch Mountains, as well as western Idaho, have not 

 been included in any of the floras of the Rocky Mountain region. As many 

 collections have been made in the part of Utah mentioned, by Edward Palmer, 

 C. C. Parry, A. L. Siler, Mrs. Almon H. Thompson, L. F. Ward, and others, and 

 especially by M. E. Jones, the whole of the states of Utah and Idaho was in- 

 cluded and at least 500 or 600 species thus added. The total number of species, 

 in the meantime, has grown to nearly 5900. 



The area covered by this flora thus includes the entire states of Colorado, 

 Utah, Wyoming, Idaho, and Montana, and extends eastward to long. 102 W. in 

 Nebraska, South Dakota and North Dakota; it also includes the Canadian prov- 

 inces of Saskatchewan and Alberta, south of lat. 55 N. (the old boundary of the 

 territories of the same name*), and the Kootenay Districts of British Columbia. 

 The Rockies extend for some distance south into New Mexico, but no attempt 

 has been made to cover any part of that state; as far as the truly mountain flora 

 is concerned, however, it is practically covered. 



As the number of known species within the area has increased, the author 

 has been obliged to shorten the descriptions in order to make the book of a con- 

 venient size; cutting down original descriptions one-fourth or more, and usually 

 avoiding repetition of characters given in the keys. The resulting brevity will 

 naturally detract from the value of the work, but otherwise the book would have 

 become too bulky to be convenient, especially in the field. The descriptions are 

 nearly all redrawn from actual specimens. The original types or duplicates of 

 the types have been consulted wherever possible, and rarely have the original 

 descriptions been merely copied or condensed. 



* The present boundary is lat. 60, but the region between lat. 55 and 60, is botan- 

 ically practically unknown. 



