562 



RELATION 1 TO ENVIRONMENT. 



region. Since the grasses are the dominant species, they con- 

 stitute the fundament of the formation. Other subordinate 

 grasses occur, and besides, the prairie is variegated by annual 

 and perennial herbs which give the formations, especially in 

 the lower areas, a spring or vernal flora, as the cat's-foot (Anten- 

 naria campestris), fennel-leaved parsley (Peucedanum fcenicu- 

 laceum), prairie clovers, etc.; and a summer-autumnal flora, as 

 golden-rods, verbenas, amorpha, etc. 



1051. The Bad Lands of Nebraska and South Dakota. The 

 vegetation in the "Bad Lands" is very meagre and is rendered 

 so for several reasons: the alkalinity of the soil, which retards 



Fig. 5066. 



Bad Lands. Firms ponderosa scopularum on the talus of buttes on the borders 

 of Sowbelly Canyon, Pine Ridge, Nebraska. Bouteloua oligostachya (grama 

 grass) formation in foreground. (Dept. Geol., Univ. Nebr.) 



absorption by the roots; the loose and crumbling condition of 

 the soil, which permits active erosion during rains and renders 

 stability of any plant precarious; the very dry air and intense 

 heat, inducing rapid transpiration; all these conditions well 

 nigh prohibit plant life. The Bad Lands are situated in and 

 near the foot-hills in the western part of these States. There 



