57 



bench lands nearer the mountains, and is usually accompanied by- 

 prairie June grass, blue grama, and some of the wheat-grasses. It 

 is not as early as prairie June-grass, but affords a larger amount of 

 forage and is much better for winter pasturage. It has a very wide 

 distribution in the Rocky Mountain region and is represented by 

 a great variety of forms, some of which, as already mentioned in 

 another connection, are valu- 

 able hay producers. 



In poor sandy soil, or in that 

 containing a large percentage 

 of alkali, the rush -grasses 

 {Sporobolus spp.) are impor- 

 tant pasture grasses. They 

 are all rather harsh and un- 

 palatable and are valuable 

 chiefly because they thrive in 

 soil that will produce none of 

 the better grasses. When for- 

 age is plentiful, stock will not 

 eat them to any great extent, 

 and the plants soon become 

 tough and woody, but during 

 seasons of scarcity these grasses 

 are, like others, kept closely 

 grazed throughout the season 

 and are tenderer and more 

 palatable. During the past 

 season a number of extensive 

 pastures were observed in the 

 Big Horn Basin composed 

 almost exclusively of fine-top 

 rush-grass or salt-grass {Sporo- 

 bolus airoides). (See fig. 21.) 

 These pastures were in alkali 

 bottoms and old lake beds, and 

 were almost the only grass- 

 covered areas of any consequence in that locality. They were grazed 

 by horses principally, and were reported to be improving with con- 

 tinual pasturing. This grass is most abundant in the southern portion 

 of the region, though occurring throughout. 



Among other rush-grasses of general occurrence in this region are 

 rough-leafed salt-grass {Sporobolus asj)erifolius), a characteristic "bad- 

 land " grass; sand rush grass {S. cryptandrus), often abundant in sandy 

 prairies and river bottoms; and prairie rush-grass {S. depauperatus). 

 There are two forms of the last occurring in this region; one found 

 chiefly in dry soil of prairies and hillsides, too small to be of much value 



Fig. 21.— Fine-top salt-grass (Sporobolut airoides). 



