THE PACIFIC COAST ALDERS. 351 



THE PACIFIC COAST ALDERS. 



BY C. C. PARRY. 



Read March 7, 188r. 



The alders, everywhere easily recognized as a natural 

 group of shrubs or trees, usually bordering water-courses, 

 present certain well-defined botanical characters comprised 

 in the old established genus Alniis. 



Widely scattered over different portions of the globe, the 

 species, variously estimated at fourteen or fifteen, are not 

 so numerous as to present serious difficulties in systematic 

 arrangement. As one would naturally expect, the species 

 most remote in geographical position present the most 

 marked specific differences, as is manifest in the Asiatic- 

 India group, as compared with those of Europe or North 

 America. At the same time, several of the high northern spe- 

 cies have a wide geographical range, in some cases apparently 

 encircling the globe; and one, at least, Alnus maritimay 

 Nutt., falls into that singular group connecting the botany 

 of Eastern North America with Japan. 



On this coast the Botany of California enumerates four 

 species; one of these, confined to the higher mountain dis- 

 tricts, is recognized as a variety of the common Eastern 

 United States species, Alnits incaiia, var. viridtscens, Wat- 

 son. 



Another well marked species, A. rubra, Bong., seems 

 peculiar to the North American Pacific coast, ranging from 

 Alaska to Central California, and apparently confined to 

 the coast districts. Some fine specimens of this latter can 

 be seen along the course of deep ravines in the vicinity of 

 Berkeley. 



Of the two other recorded species to be considered, viz: 

 Alnus rliomhifoUa, Nutt., and A. ohlongifolia, Torr., which, 



