27 



(3) Grassland Subtype 



The .iuniner-prassland subtyoe (Figure 24) had no other shrub 

 species present besides rocky mountain juniper. Its open 

 stands were covered with a mixture of grasses and forbs, 

 the primary species being bluebunch wheatgrass, little bluestem, 

 blue grama, cheatgrass, broom snakeweed. Hood's phlox [Phlox 

 hoo di-i) , fringed sagewort and cudweed sagewort [AfitzmA^ila 

 P.iLdovA.C'iana) . 



Sagebrush/Grassland Series 



There were four subtypes defined in the sagebrush/grassland 

 series. Big sagebrush and silver sage {A^tzmZ-dia cana) were 

 the primary shrub soecies in two of the subtypes. Skunkbush 

 was the dominant shrub species in the third subtype. Few to 

 no shrubs were found in the xeric grassland subtype. 



(1) Big Sagebrush Subtype 



Big sagebrush was the dominant shrub in this subtype (Figure 25). 

 It usually occurred on flat to medium slopes. Various grasses 

 and forbs were found on this subtype Including Junegrass, blue 

 grama, western wheatgrass, sedges (Ca^ex spp.), needle-and- 

 thread. Japanese chess, cheatgrass, false-tarragon sagewort 

 [KKtzmliila dfiacunculai) , field chlckweed [Czfia'dtium a^uen-6e), 

 Hood's phlox, salsify and pale bastard toad flax [ComandfLa 

 ambe.llata] . 



(2) Silver Sagebrush/Greasewood Subtype 



This subtype occurred on alluvial valley floors (Figure 26). On 

 many study areas it was the most common lowland vegetation type. 

 Almost all coulee bottoms and small valleys had silver sagebrush 

 stands. Greasewood {SaH-cobatU't vzfimyicutatU'l,] stands were best 

 developed along the Tongue River bottoms. Ground cover included 

 occasional prairie rose {Ro&a afikaniana] stands. A variety of 

 grasses and forbs including Japanese chess, cheatgrass, false 

 tarragon-sagewort and salsify were found In the silver sagebrush/ 

 greasewood subtype. 



(3) Skunkbush Subtype 



The skunkbush subtype (Figure 27), also referred to as the 

 deciduous shrub subtype, occurred on rocky south facing slopes, 

 where skunkbush was the dominent species. Other species present 

 were yucca, fringed-sagewort , desert alyssum {AlyA6um de-4eA.to^um) , 

 broom snakeweed, bluebunch wheatgrass, little bluestem, needle- 

 and-thread and red leaf three-awn. 



(4) Xeric Grassland Subtype 



The grassland subtype (Figure 28) was open grassland with a few 

 isolated shrub patches. Many grass species were found depending 

 on soil and moisture conditions. Bluebunch wheatgrass, western 



