XIV 
INTRODUCTION. 
made to explain why two different standards are used in the same 
work. The altitudes are those at which the different species grow 
within the state of Colorado, so far as records show. Many of the 
plants which grow at an altitude of 14,000 feet in Colorado, grow 
at sea-level along the arctic coast. 
The nomenclature used is in principle agreeing with the so-called 
American Code adopted at a meeting in Philadelphia, printed in the 
Bulletin of the Torrey Botanical Club in May, 1904, and submitted to 
the International Botanical Congress at Vienna last summer, with 
a few modifications resulting from a compromise with the European 
botanists. This code as modified is now followed by a majority of 
the leading systematic botanists in this country. The fundamental 
principle underlying is that the selection of generic as well as specific 
names should always be governed by the priority of publication. The 
European botanists have adopted this principle as far as specific 
names are concerned, but most of them are not yet willing to apply 
the same rules to generic names. In the older publications on the 
Rocky Mountain flora the so-called Kew Rules were adhered to, 
which after all gave very little consideration to priority. Many of 
the names in this catalogue will be unfamiliar to some of its users, 
but in most cases the old names are given as synonyms in italic and 
also in the index. In the index there has been inserted also a few 
common names not given in the text followed by the equivalent latin 
generic name in parenthesis. Most of these are local names un¬ 
known to the author before they appeared in a recent publication on 
western botany. 
With regard to generic limitations, the author belongs to that 
radical school which believes in small genera with closely related 
species rather than in larger ones with a heterogeneous mass of 
different groups of plants having relatively little relationship to each 
other. Many of the older genera have therefore been divided. The 
division of genera as well as species has gone perhaps a little further 
than many would think advisable, but the author has tried to be con¬ 
sistent in his work. 
The author has not published any new species or genera in this 
work. He has also tried to avoid the publishing of new names or 
new combinations of names. Anything that had not been published 
before, the author has endeavored to publish in the Bulletin of the 
Torrey Botanical Club while the catalogue was being set in type. 
The reasons for so doing are the following: (1) The publication of 
technical descriptions should be limited to technical books and peri- 
