THE COASTAL SAGEBRUSH. 161 



of this as a sagebrush association was made in 1918, and as a consequence it 

 has received Uttle or no special study. It owes its character to Artemisia 

 calif ornica as the major dominant. This is a typical sagebrush, resembling 

 Artemisia JUifolia closely in habit and A. tridentata in climax qualities, espe- 

 cially when it occurs as a pure consociation. 



CONSOCIATIONS. 

 Artemisia caufornica. Salvia apiana. 



Salvia melufera. Eriogonum fasciculatom. 



Salvia leucophylla. 



The most important consociation is Artemisia califarnica. It not only 

 occurs in most of the groupings, but it also ranges widely along the Coast 

 hills as a pure community. Eriogonum fasdculatum is the most frequent as- 

 sociate of the sagebrush, often with Salvia mellifera. Salvia apiana is restricted 

 to the southern part of the area, and is more subclimax in nature than the 

 others. Eriogonum fasdculatum, with the variety polifolium, has much the 

 widest range, forming extra-associational communities in the Larrea desert, 

 and the southwestern edge of the main sagebrush association. In southern 

 California and Lower California, four dominants are frequently associated. 

 Farther north the community is regularly constituted by Artemisia cali- 

 f ornica, Eriogonum fasdculatum and Salvia mellifera, or leucophylla. This is 

 the typical grouping of the association, though any two of the dominants may 

 occur together in this area. The association shows the usual tendency to 

 break into pure consociations toward its borders. Along the edge of the desert 

 it is represented chiefly by Eriogonum fasdculatum, and on the western slopes 

 of the Coast Range by Artemisia calif ornica (plate 35). 



The Coastal sagebrush association is in intimate contact with the Adenos- 

 toma-Ceanothu^ chaparral and the Larrea desert. In former times it must 

 have touched the Stipa bunch-grass community along much of the interior 

 valley, and to-day the two are much mixed in southern California. Through- 

 out its area, the sagebrush lies just below the Adenostoma consociation of the 

 chaparral. The ecological requirements of the latter are so nearly equivalent 

 to those of Salvia and Eriogonum in particular that these often seem an 

 integral part of the chaparral. All the dominants mix so intimately with 

 Adenostoma along the ecotone, owing to the characteristically diverse topog- 

 raphy, that an absolute line of separation is out of the question. This is so 

 often true of ecotones, however, that it does not affect the vaUdity of the 

 sagebrush association, as is readily seen when typical areas of the two forma- 

 tions are compared. This conclusion is supported likewise by a characteristic 

 difference in the shrub form, and by the systematic relationships, as pointed 

 out before. Toward the desert the intrusion is even greater and is best 

 illustrated on the south side of the Mohave, where Eriogonum fasdculatum 

 is regularly mixed with such desert dominants as Larrea, Salvia carnosa, 

 Salazaria mexicana, Trictiostema lanatum, and Yucca, as well as frequently 

 with Artemisia tridentata, Chrysothamnus nauseosus, and Atriplex canescens. 



No factor studies have been made in this association and the sequence of 

 the dominants is a matter of inference. The five species are closely equivalent, 

 though the topographic and serai relations indicate a definite and constant 

 sequence. Artemisia calif ornica, Uke A. tridentata, is the most mesophytic 

 and under static climatic conditions would tend to form a pure climax. Salvia 

 meUifera and S. lev^xtphylla follow closely in requirements, while Eriogonum 



