Southeastern Washington and Adjacent Idaho. 77 



mocallis, and Sidalcea, but not infrequently Opulaster grows in 

 such situations as to replace the more xerophytic grasses and 

 Balsamorhiza. 



Chaparral that is so dense as to almost exclude other vegetation 

 is characterized in early spring and before the leaves appear by a 

 layer society of Erythronium grandiflorum. These lilies are 

 often so numerous as to give the appearance of a yellow carpet 

 'under the shrubs. In less shaded areas Ranunculus glaberrimus 

 and Olsynium grandiflorum are plentiful. The Opulaster con- 

 socies is very conspicuous in May, when its countless white blos- 

 soms give a distinct tone to the landscape. Likewise, in late 

 August and September the reddish-tinted drying leaves form a 

 pleasing variety to the monotonous brown of dry vegetation. 



While Opulaster frequently characterizes considerable areas 

 alone, it is not infrequently associated with the buckbrush, 

 Ceanothus sanguineus. Indeed, the latter shrub may sometimes 

 become so abundant as to make up half of the mictium. The 

 buckbrush because of its oily seeds, is a very important and fat- 

 tening food for sheep on the summer range. Numerous other 

 shrubs, such as Holodiscus discolor, Prunus emarginata, and 

 species of Ribes are less important components of this consocies. 



Prunus Consocies. Local areas on the buttes are often charac- 

 terized by growths of Prunus emarginata. These vary from a 

 rather open growth of stunted shrubs only three feet high to 

 dense copses in which the cherry takes on the stature of a small 

 tree. The characteristic occurrence of this community in dry 

 open places is of considerable ecological significance. I have not 

 infrequently found invading pines extending their territory from 

 sheltered slopes into the drier areas under cover of these shrubs. 

 Frequently the pines may be overtopping the cherries and indeed 

 beginning to replace them, yet a count of annual rings usually 

 shows that the latter were the pioneer woody plants. 



Ceanothus Consocies. On the exposed slopes of Cedar Moun- 

 tain and adjacent buttes, but seldom found elsewhere in the re- 

 gion, the sticky laurel, Ceanothus velutinus, often dominates. 

 This evergreen, semi-procumbent shrub, while seldom reaching a 

 height of over 46 feet, has numerous long branches which spread 



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