Southeastern Washington and Adjacent Idaho. 



57 



the root-systems of many of the most important prairie plant 

 species and it is there pointed out that the response of many of 

 the plants to severe environmental conditions is met by well de- 

 veloped and extensive root- systems (17). Figs. i$a, i$b, and 

 15^ show in part the results of these investigations as regards 

 root type and depth of penetration. 



Standing well above most other prairie vegetation and con- 

 spicuous not only for its size but also often for its great abun- 

 dance is Leptotaenia multifida. This large, much branched, un- 

 belliferous plant occurs quite commonly on both dry and moist 



FIG. I5 & . S, Sieversia ciliata. W , Wyethia ample xicaulis. L. I, Lupinus 

 leucophyllus. L. o, Lupinus ornatus. P, Poa sandbergii. L, Leptotaenia 

 multifida. A, Agropyron spicatum. 



hillsides. It often characterizes rather large areas, but even if 

 occurring sparsely it is nevertheless very conspicuous and espe- 

 cially in June, when, after flowering, the leaves turn yellow be- 

 fore drying up. 



Erythronium grandiflorum constitutes a well-marked prevernal 

 aspect society on moist north hillsides from early April to the first 

 week in May. Even before the plants open their large golden 



57 



