46 University of California Publications in Botany [Vol. 9 



changes sufficiently to cause common recognition, lie the "high moun- 

 tains" or "high Sierra" of Calif ornian geography, a region full of 

 interest to the visitor whatever his primary motive for journeying into 

 it may be. To the geologist, the high mountain countrj^ offers a vast 

 tract wherein all the forces of dynamical geology have operated upon 

 a complex of diversely derived rocks to produce every conceivable 

 modification of topographic detail; to the zoologist, the "high 

 Sierra" is inviting because it is one of the few areas yet remaining 

 in the west where animals are really wild and not "protected" to 

 tameness ; to the botanist its appeal lies not merely in the study of 

 the individual plants, but also in the investigation and attempted 

 solution of the problems presented by their distribution. 



It is generally agreed that the presence of certain plants and 

 animals shall be taken as indicating the existence in any particular 

 place of a certain life-zone, these plants being styled "zone indica- 

 tors." Coville^" has pointed out how unsatisfactory herbaceous plants 

 are in this respect and particularly annuals (i.e., species of Gayophy- 

 tum, Gilia, etc.), which occur throughout the series of zones, blooming 

 in the lower mountains in spring and foiuid in flower till the end of 

 August or early September at higher and higher altitudes ; such 

 plants cannot be disregarded in a complete survey of the vegetation 

 of the higher mountain region but their presence indicates that the 

 scheme of life-zones is at best an inadequate expression of the life 

 conditions, which, for annuals at least, change with the advancing 

 season. As a result of their great altitudinal range, we find in the 

 meadows and forests of the higher mountains plants which have their 

 zones of greatest frequency hundreds or thousands of feet nearer sea 

 level. This is in fact the criterion by wliich to judge the zonal position 

 of a plant : in what zone is it most frequently seen, or where can it be 

 most reasonably expected? When this measure of pertinence is kept 

 in mind, zone indicators serve a useful purpose and give to the 

 expressions "Canadian flora of the Sierra" or "Arctic-alpine flora of 

 the Cascades" meanings readily understood by students of western 

 plants. With this understanding of the term, it is believed that the 

 plants named in the following lists best serve in the higher Sierra 

 Nevada as zone indicators. Plants queried are included in the lists 

 provisionally. 



