182 CUMAX FORMATIONS OF WESTERN NORTH AMERICA. 



frequent dominants of the Rocky Mountain community. It also shows 6 

 other important dominants, 5 of which, Cercocarpus ledifolius, FaUugia, 

 Cotoania, Coleogyne, and Arctostaphylus pungens, are of greater significance 

 than in the Rocky Mountains, while one, Ceanothus cuneatus greggii, is largely 

 absent in the latter. A comparison of the subclimax chaparral with the 

 Rocky Mountain likewise shows a close relationship ; 4 of the chief dominants 

 of the one are equally important in the other, and all but 2 of the 13 are present 



DOMINANTS. 



'Merely present. 



in the Rocky Mountain region. A lesser degree of resemblance is found 

 between the Coast and the Rocky Mountain chaparral, though their forma- 

 tional relationship is clear. Of the 6 most typical dominants of the former, 

 but 1 occurs in the latter, while the most characteristic dominant of the 

 Rocky Mountains, QiLercus undulata, is completely lacking, unless indeed it 

 is represented by Q. garryana. On the other hand, the 2 communities possess 

 8 important dominants in common (plate 41). 



