PREFACE 



In Europe, pocket manuals or so-called excursion floras have been very 

 ipopular. These contain scarcely more than keys to the plants of the regions 

 treated. The author, therefore, thought that a reprint of the keys found 

 in his Flora of the Rocky Mountains and Adjacent Plains* would be 

 useful in a similar way; not that he thought that this little book would 

 be sufficient in studying the vegetation of such a vast territory, for keys 

 are never wholly satisfactory. A few hints may be given, however, to 

 show how and to whom this book may be useful. 



The Key may be used in connection with the Flora, or independently. 

 The Flora is too big a book to carry conveniently on a field excursion. The 

 Key is easily carried in a pocket, and by means of it, the preliminary study 

 and determinations can be done in the field while the flowers are fresh, 

 and a more thorough study can be made at home afterwards with the aid 

 of the Flora. In this way, the Key may be very useful to the field-botanist, 

 the forester, the ranger, and the rachsman, who studies the vegetation on 

 horse-back or on foot. It may also be conveniently used in the classroom, 

 together with the Flora. In many cases the school or the students could 

 not afford to buy a copy for each student or each two members of the class, , 

 while it could be done in the case of a less expensive book. The drilling 

 in how to determine a plant could be done by means of the Key, and when 

 the plant is tentatively determined, the verifications may be done by means 

 of one or two copies of the Flora, the description in it being read by the 

 teacher or a member of the class. 



The Key may also be used independently. It may conveniently be 

 used as a check-book for recording the local flora. Where an inexpensive 

 book is desired, it will be useful, if not sufficient, for the classification of 

 the plants of the Rockies. Many amateur botanists do not care as much 

 for the technical description as for knowing the scientific and common 

 names of the flowers. In this case, the Key may be sufficient, as all the 

 accepted scientific names found in the Flora are also found in the Key. 

 So are also all the common or popular names, except a few which were 

 mentioned in the text and which apply merely to that particular species. 

 These names are, however, mostly given in the index. In the index are 

 also given- the most important synonyms of the scientific names of the genera, 

 with a reference to which genus each belongs. 



The area covered by the Key, as well as by the Flora, include the entire 

 states of Colorado, TJtah, Wyoming, Idaho, and Montana, and extends 

 eastward to Long. 102 W. in Nebraska, South Dakota and North Dakota; 

 it also includes the Canadian provinces of Saskatchewan and Alberta, south 

 of Lat. 55 N. (their old northern boundary), and the Kootenay Districts 

 of British Columbia. The book contains the keys to 1038 genera and 5897 

 species of flowering plants and fernworts, in other words of all that have 

 been recorded within the region. 



It was also advisable to reprint the Glossary of the Flora, as it would 

 be useful to those not too familiar with the scientific terms. 



P. A. Rydberg. 

 New York B6tanical Garden, September, 1918. 



* See advertizement on page 305 



