150 W. S. Cooper 



The genus Atriplex is preeminently characteristic of saline 

 habitats — sea strands, and steppes and deserts with salt-impreg- 

 nated soils (Volkens, 1893). Throughout the temperate and sub- 

 tropical regions of the earth, wherever such an environment is 

 found, species of Atriplex form an important element in the 

 vegetation. The great majority of the North American members 

 are inhabitants of the semidesert regions of the Southwest. Sev- 

 eral species of southern California, Baja California, and the 

 Mexican mainland are rather closely restricted to the strand. 



Abronia. — ^Two species of this genus are important members 

 of the foredune community; a third is common but of lesser 

 ecologic significance. A. lati folia Eschsch. (fig. ig), one of the 

 most important foredune builders, ranges from Vancouver Island 

 (Comox and Ucleulet) southward to Santa Monica in southern 

 California. A. maritima Nutt. (fig. \K) has a more southern 

 range, from Morro, San Luis Obispo County, California, to the 

 tip of Baja California, and on the Mexican coast to Tepic at least. 

 A, umhellata Lam. (fig. i/) is a variable species, or a species- 

 complex, of little importance as a builder of hillocks. Standley 

 (1918) recognizes five forms as specifically distinct. A. aciitalata 

 Standley, found in a few localities in the Puget Sound region, 

 is entirely isolated from the others. A. breviflora Standley 

 inhabits the coast of Del Norte, Humboldt, and Mendocino 

 counties, California. Typical A. umbellata ranges from Marin 

 County, California, to southern California. A. cdba Eastw. and 

 A. minor Standley are found on the coast of southern California, 

 and the former also on the islands off the coast. A sixth form, A. 

 gracilis Benth., rather more distinct than the others, occurs from 

 southern San Diego County to Magdalena Bay, Baja California. 



Abronia is a North American genus, occurring chiefly in the 

 western United States. One or two species extend into south- 



