60 University of California Publications in Botany [Vol, 9 



passively transported from station to station, but by what agency is 

 at present obscure. In spite, however, of the fact that the Sierra 

 would seem to offer as suitable a habitat for the arctic-alpine flora, 

 or for the "Glazialpflanzen" of Engler'*" as the Cascades or the 

 Rockies, we find its flora, as exhibited in the following list, to be 

 singular among the boreal floras of the west in its paucity of high 

 arctic types. Of the plants found at high altitudes in the Rockies 

 and in the mountains of AVashington and British Columbia and rang- 

 ing north to the Arctic, a significant number have failed to reach the 

 Sierra, though not a few have entered the mountains of northern 

 California. 



STATISTICAL ABSTRACT FROM THE ANNOTATED LIST 



FLOEISTIC COMPOSITION OF THE BOEEAL FLORA OF THE 



SIERRA NEVADA 



That part of the high mountain flora of the Sierra Nevada com- 

 posed of vascular plants, is made up of 57 families divided into 243 

 genera and 633 species.* Five of the families belong to the pterido- 

 phytes. The spermatophyte families include the single gymnosperm 

 family of Pinaceae, leaving the flowering-plants to be divided among 

 51 families. None of the plant families are peculiar to the region 

 covered by this report. 



The 5 families of pteridophytes include 14 genera; the P0I3'- 

 podiaceae with 10 genera and the other 4 families with 1 genus 

 each. Although the Polypodiaceae include the majority of the species 

 (13 out of a total of 20), the genus-species ratio is less in this family 



* It is freely admitted that the basis for this report is a concept of the species 

 (and of the subordinate categories) whicli is frankly conservative; I have not 

 intentionally rejected any new definition merely because of its newness but have 

 sought to examine it carefully and determine, as best I could, its value. Many 

 species recently proposed have seemed to me of no merit whatever, to be in fact 

 mischievous, since their definition interferes with what, in my opinion, is tlie 

 natural relationship. Most of tlie species here atlmittetl as components of the 

 high mountain flora of the Sierra were defined in a period Avheu the concept of 

 the species was more comprehensive than that held by many botanists of today, 

 and it is probably true that many of the species recognized in the Annotated List 

 will seem to some too inclusive, just as many of the varieties and forms included 

 will appear to have good claims to be considered as deserving of higher taxo- 

 nomic rank. It is believed, hoAvever, that this attitude strengthens, rather than 

 weakens, any conclusions which now- may be drawn Avith regard to floristic rela- 

 tionships. Certainly if one were seeking to establish the thesis that the flora 

 of every mountain range of the west is a thing apart, he could find abundant 

 verbal justification in the numerous descriptions of local races or even of indi- 

 vidual abnormalities which have been issued as specific diagnoses. It is hoped 

 that the judgments concerning these matters expressed in the List will not be 

 found wanting in a significant number of cases. 



