182 



The Plant World. 



extends much farther down, marking the limit of tree growth 

 down the mountain side, frequently forming extensive forests. 

 The herbaceous plants in these forests are the same as found in 

 pine forests. Astragalus, Lupines, Larkspurs, Poas, Polemon- 

 iums, etc. 



The sage brush (Artemisia tridentata) is found not only on 

 the east slope of the Rockies, but in the great interior basin in 

 southern Idaho to the foothills of the Blue Mountains and east- 



i 



Fig. 1. The Sagebrush {Artemisia iridentada) in the Salt Lake Basin, 

 Utah, with Salt G/ass {Distichlis spicata) in the foreground. Photo by 

 L. H. Panimel. 



ward from the Cascade Mountains. In this interior country it 

 reaches its greatest size. Along the streams, especially Snake 

 River, there is a great deal of what is commonly called the 

 Cottonwood {Populus angusiifolia) ; on the banks of the stream 

 the sandbar willow (Salix fluviatilis), an abundant species ;while 

 a form of the almond leaf willow (Salix amygdalordes) is com- 

 mon. The shiny willow (Salix lasiandra), a beautiful species 

 which should be cultivated in the eastern states, is abundant 

 at higher altitudes in the Rockies, the Uintahs, and the Wasatch 

 mountains. Of the roses, the most conspicuous along the 

 streams is the Fendler's Rose (Rosa Fendleri). On the dry, 



