6 TREES AND FLOWERS OF 



identification. A selection has therefore been made 

 of about one hundred of the plants most frequently 

 seen and inquired about by visitors to the Park. 



In this book, technical terms and treatment have 

 been avoided whenever possible. For the most part 

 the genus is the smallest group considered, as the 

 average visitor is not interested in fine distinctions 

 among species; and even if he were he would get 

 small comfort from the professional botanists, who 

 are too often in hopeless disagreement among them- 

 selves. For those who are interested in more exact 

 determinations, there is no substitute for the complete 

 floras of Coulter and Nelson and of Rydberg, covering 

 the whole Rocky Mountain region. Mention must also 

 be made of "Rocky Mountain Flowers," by Clements 

 and Clements, a work combining a high degree of 

 scientific accuracy with adaptability for popular use, 

 and illustrated with finely colored plates. 



No artificial "key" has been included in this work, 

 for it has been the writer's experience that these are 

 rarely, if ever, used by the layman. The usual prac- 

 tice is to turn the leaves of the book until a picture 

 is found that corresponds with the flower under ex- 

 amination. 



The plants are grouped according to their growth- 

 form, as trees, shrubs and herbs, but beyond that they 

 are left in approximately the same order in which 

 their family affinities place them. This sets flowers 

 of similar form and evolutionary history together, 

 and has at least the virtue of being a natural arrange- 

 ment. 



Frank E. A. Thone. 



