Southeastern Washington and Adjacent Idaho. a7 
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 4-6 feet, has numerous long branches which spread 
Pi 
