144 W' S. Cooper 



brush. In selecting the Ust for floristic study, an effort has been 

 made to include only those species that are characteristically 

 coastal. Naturally there is abundant opportunity here for differ- 

 ence of opinion. 



In Baja California the coastal sagebrush type is replaced by 

 another shrub community with desert affinities. Our knowledge 

 of it is too limited to warrant its consideration. 



The concept of the species here adopted is a broad one. Accept- 

 ance of the larger unit as fundamental, with full recognition of 

 the smaller units contained within it, seems the most useful pro- 

 cedure in floristic study. Of the genus, also, the concept is usually 

 a broad one, and for the same reason. It has seemed necessary 

 to replace some long-familiar names with unfamiliar ones; when 

 this is done, the better-known name is added in brackets. 



RANGES OF SPECIES 

 Species of Strand and Shifting Dunes 



Poa.—Thret species of Poa, probably related, are character- 

 istic dune plants on the northern Pacific coast of the United 

 States. Mutually equivalent ecologically, they are found usually 

 on feebly moving sand in relatively sheltered places not in im- 

 mediate proximity to the shore. Poa confinis Vasey (fig. la) goes 

 farthest north (Comox, east side of Vancouver Island) and ex- 

 tends southward to Mendocino County, California (Inglenook). 

 It is extensively overlapped by P. macrantha Vasey (fig. ic), 

 which goes not so far north (Whidbey Island, Puget Sound), but 

 a Htde farther south (Point Arena, Calif.). P. douglasii Nees 

 (fig. lb) overlaps the first two in northern California; it begins 

 at Point St. George, Del Norte County, and extends farther 

 southward than the others to Point Sur, Monterey County. 



