ally present with cover exceeding 1% include Koeleria cris- 

 tata , Poa sandberqii , and Stipa comata . 



Physical Setting. — The type occurs on flat to steep residual 

 mountain slopes and rolling uplands at elevations between 6000 

 and 7600 feet. The total cover of soil, gravel, and rock 

 ranges from 40 to 60% and the soil surface is usually stable 

 with little or no evidence of accelerated erosion. 



Parent materials include igneous and metamorphic rocks. 

 Soils are generally Argiborolls and either lack coarse frag- 

 ments or are gravelly to very gravelly. The soils are gener- 

 ally not calcareous and, thus, are not effervescent. Soil 

 depth ranges from shallow to very deep. Textures are mostly 

 loams to clay loams. Available water holding capacity ranges 

 from low to high. 



Adjacent Communities. — The Artemisia tridentata/Agropyron 

 spicatum type occurs on more xeric and warmer sites. 



Other Studies. — This type has been described in Montana by 

 Mueggler and Stewart (1980). 



10. Artemisia tripart it a/Fes tuca idahoensis Type 



(ARTTRP/FESIDA; threetip sagebrush/Idaho fescue; G5 S3) 



Vegetation. — Artemisia tripartita . Festuca idahoensis . and 

 Stipa comata are abundant within this community type. Other 

 species that are generally well represented include Artemisia 

 f riqida . Chrysothamnus viscidif lorus , Tetradymia canescens , 

 Lupinus sericeus, Koeleria cristata , and Poa sandberqii . 



Physical Setting. --The type occurs on gently rolling uplands 

 at elevations between 6500 and 7000 feet. Bare soil cover 

 ranges from 10 to 30% and coarse fragment cover is generally 

 less than 20%. The soil surface is usually stable with little 

 or no evidence of accelerated erosion. 



Parent materials include eolian deposits and igneous 

 rocks. Soils generally lack coarse fragments, are not 

 calcareous, and are deep to very deep. Textures range from 

 sands to sandy loams and available water holding capacity 

 ranges from low to medium. 



Adjacent Communities. --The Artemisia tripart it a/ Fes tuca 

 idahoensis and A_^ tridentata/Festuca idahoensis types are 

 ecologically similar. Of the two types, the A_^ tripartita 

 type generally occurs on more xeric sites. In the Centennial 

 Valley, the Aqropyron dasystachyum/Phacelia hastata type is 

 often found on adjacent sand dune and blow out sites. 



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