PALOUSE PRAIRIE 293 



The disclimax of annual grasses so characteristic of the Cahfornia 

 prairie has a counterpart in the Bromus cover composed ahnost wholly 

 of B. tectorum. With this are frequently found two other annual 

 dominants, Sisymbrium altissimum and Lepidium perfoliatum, most 

 abundantly in regions of cultivation. Generally, Bromus and Arte- 

 misia occur together to constitute the savanna typical of the area of 

 this association. 



Influents. The bison was present in small herds in southern Idaho 

 and northern Utah, but decreased in numbers westward; a few re- 

 mains have been found in extreme northeastern California. The 

 pronghorn antelope was originally distributed over most of the Pa- 

 louse prairie, and at one time there were large herds in eastern Ore- 

 gon. The badger was present throughout and has persisted even after 

 overgrazing caused extensive invasion by sagebrush. The area is well 

 provided with ground squirrels, coyotes, and formerly wolves also. The 

 so-called sage grouse {C entrocercus urophasianus [Bonap.]) belongs 

 properly to this region, and it also has remained after the practical 

 removal of the grasses. The area in which this grassland occurs con- 

 tains large outcrops of rock and is dissected by numerous deep val- 

 leys, giving a characteristically different set of local conditions in 

 serai stages (Merriam and Stejneger, 1891; Dice, 1923; Preble, 1925; 

 Wight, 1925; Bailey, 1936). 



