THE COASTAL CHAPARRAL. 191 



which range to southern Utah, western Colorado, southern New Mexico, 

 trans-Pecos Texas, and Mexico, where they blend with the Petran association. 

 The general altitudinal range of this chaparral is from sea-level to 5,000 to 

 7,000 feet, but the actual limits vary greatly with the region and the slope. 

 The normal upper limit is rarely above 5,000 feet (plate 44). 



DOMINANTS. 



Adenostoma fasciculatum. Arctostaphylus manzanita. Heteromeles arbutifolia. 



Ceanothus cuneatus. Arctostaphylus pungens. Dendromecum rigidum. 



Arctostaphylus tomentosa. Arctostaphylus bicolor. Eriodictyum californicum. 



Quercus dumosa. Rhamnus crocea. Adenostoma sparsifolium. 



Ceanothus divaricatus. Rhamnus californica. Prunus ilicifolia. 



Ceanothus sorediatus. Rhus integrifolia. Prunus demissa. 



Ceanothus dentatus. Rhus diversiloba. Cercocarpus ledifolius. 



Ceanothus hirsutus. Rhus laurina. Amelanchier alnifolia. 



Ceanothus verrucosus. Rhus ovata. Holodiscus discolor. 



Arctostaphylus glauca. Cercocarpus parvifolius. 



This list is in essential agreement with the more complete list of Cooper 

 (1919) for the California chaparral. However, a number of species of limited 

 range have been omitted. Simmondsia californica is thought to belong more 

 properly to the desert scrub and the position of Adolphia californica is uncer- 

 tain. Eriodictyum californicum is the typical dominant in burns and other 

 disturbed areas, but is included because of its frequence. 



More than two-thirds of the dominants listed are confined to California and 

 Lower California. Of the four major dominants, Ceanothus cuneatus and 

 Arctostaphylus tomentosa extend to Oregon and British Columbia, respec- 

 tively, while of those of considerable importance, Arctostaphylus pungens, 

 Rhamnus californica, R. crocea, Cercocarpus parvifolius, and Amelanchier 

 alnifolia extend through Arizona into the Petran association, where the last 

 two become major dominants. 



Groupings. — The number of groupings is large and only a few of the most 

 common can be indicated. The four major dominants frequently occur in 

 pure stands of considerable size, and this is sometimes true of other important 

 dominants as well. The general rule, however, is a mixture of several species, 

 usually 5 or more. Adenostoma is the chief dominant from Lake County 

 southward in California, usually associated with several of the following: 

 Arctostaphylus tomentosa, A. glauca, Ceanothus cuneatus, Quercus dumosa, 

 Heteromeles arbutifolia, Cercocarpus parvifolius, and Rhamnus californica, 

 several of which may become more important locally than Adenostoma. The 

 latter drops out beyond Trinity County, and Ceanothus cuneatus and Arc- 

 tostaphylus tomentosa form the regular groupings as far as northern Oregon, 

 where the former disappears. Rhus diversiloba occurs with them frequently 

 and Cercocarpus, Amelanchier, Purshia, Holodiscus, and Philadelphus are 

 increasingly associated with them to the northward. In the San Gabriel 

 mountains of southern California, Adenostoma, Quercus dumosa, Ceanothus 

 divaricatus, Arctostaphylus, and Cercocarpus are the most important domi- 

 nants, while in the neighboring San Bernardino Range the grouping is prac- 

 tically the same, but with Cercocarpus much more important (Leiberg, 1900 : 

 419, 439). On San Jacinto Mountain, Adenostoma fasciculatum and A. sparsi- 

 folium constitute 50 to 75 per cent of the chaparral below 5,000 feet, with 



