26 THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 



The Climax Chaparral Association. 



The climax chaparral is the dominant community over the whole 

 of the southern Coast Ranges and the mountains of southern Cali- 

 fornia and northern Lower California. Only the highest summits, 

 controlled by conifers, and the more mesophytic north slopes, 

 inhabited by broad-sclerophyll forest, must be excepted. North- 

 ward in the north Coast Ranges the chaparral shares its control 

 more and more with the broad-sclerophyll trees, and opposite the 

 northern end of the Sacramento Valley it disappears entirely as a 

 dominating community. In the southern Sierras it is of great 

 importance, occupying a wide belt in the foothills. In the northern 

 Sierras its continuity is broken, and this is not strange, since the 

 conifers of the montane forest here reach the valley floor. The 

 present range of the climax chaparral is indicated in a very general 

 way by the range of its most important species, Adenostoma fas- 

 ciculaium (plate 3). In addition, I believe that there are certain 

 extensive areas now inhabited by grasses and by half-shrubs that 

 climatically and potentially are chaparral regions (p. 76). 



Since the climax chaparral is by far the most widely extended 

 and diversified of the broad-sclerophyll communities, it is natural 

 that the present list of species should be the longest. The following 

 are all evergreen, except that Quercus dumosa is barely so. One 

 asterisk (*) indicates that the species is also of importance in the 

 conifer forest chaparral; two asterisks (*) that it is important in that 

 and also in the broad-sclerophyll forest. 



Castanopsis chrysophylla minor.* 

 Quercus chrysolepis.** 



dumosa. 



durata. 



wislizeni fi-utescens.** 

 Dendromecon rigidum. 

 Heteromeles arbutifolia. 

 Cercocarpus betulsefolius. 

 Adenostoma fasciculatum. 

 sparsifolium. 

 PrunuB ilicifolia. 

 Xylothermia montana. 

 Cneoridium dumosum. 

 Rhus integrifolia. 



Rhus laurina. 



ovata. 

 Rhamnus californica.* 



crocea. 

 Ceanothus crassifolius. 



cuneatus. 



dentatus. 



divaricatus. 



hirsutus. 



megacarpus. 



papiilosus. 



rigidus. 



sorediatus. 



verrucosus. 



Garrya elliptica. 

 Comarostaphylis diversifolia. 

 Xylococcus bicolor. 

 Arctostaphylos andersonii. 



glauca. 



hookeri. 



manzanita. 



montana. 



pumila. 



stanfordiana. 



tomentosa. 



vestita. 

 Eriodictyon californicum. 



With so large a list of species there is naturally great diversity in 

 the composition of the association. Anyone given to splitting of 

 hairs would easily separate many communities of lower rank. This 

 is in part due to slight habitat differences, but also in an important 

 degree to the great number of species with restricted range and to 

 the frequent occurrence of fires, which result in multitudinous com- 

 binations of species, depending upon which are able to survive or to 

 repopulate the area burned. It is easy to recognize, however, 

 throughout the length and breadth of the region, one striking and 



