Festuca idahoensis and P^ menziesii/Agropvron spicatum . Adja- 

 cent grasslands and shrublands include Aqropyron spicatum/Poa 

 sandberqii and Artemisia trident at a/ Aqropyron spicatum . res- 

 pectively. 



Other Studies. --This type has not previously been reported in 

 Montana but has been reported in Idaho, Utah, and Wyoming 

 (Bourgeron and Engelking 1991) . 



Juniperus scopulor\im/ Artemisia tridentata Type 

 (JUNSCO/ARTTRI; Rocky Mountain juniper/big sagebrush; G2? S2?) 



Vegetation. -- Juniperus scopulorum is the only tree species 

 present. Species exceeding 5% cover in the undergrov/th 

 include Artemisia tridentata , Opuntia polyacantha , Aqropyron 

 spicatum , Aristida lonqiseta . Bouteloua gracilis . Oryzopsis 

 hymenoides , and Stipa comata . 



Physical Setting. — The type occurs on plateaus and residual 

 mountain slopes at elevations between 5500 and 6000 feet. The 

 total cover of soil, gravel, and rock averages 70%. The soil 

 surface is sometimes unstable because of a lack of adequate 

 vegetation cover. 



Soils are generally shallow or very shallow (i.e., 

 lithic) and are derived from igneous or sedimentary parent 

 materials and feature strong to violent effervescence. Tex- 

 tures vary from sandy loams to silt loams and are gravelly to 

 very gravelly. Available water holding capacity varies from 

 low to medium. 



Adjacent Communities. — The Artemisia tridentata/ Aqropyron 

 spicatum community type often occurs on adjacent less rocky 

 sites with deeper soils. More mesic sites with similar soils 

 feature the Juniperus scopulorum/Cercocarpus ledifolius 

 community type. 



Other Studies. --This type has not been previously described 

 but has been reported as a possible type in Colorado and 

 Wyoming (Bourgeron and Engelking 1991) . 



Juniperus scopulorum/Cercocarpus ledifolius Type 

 (JUNSCO/CERLED; Rocky Mountain juniper/mountain mahogany; G3 

 S3) 



Vegetation. -- Juniperus scopulorum is the only tree species 

 present. Abundant Cercocarpus ledifolius characterizes the 

 undergrowth. Other species that are generally present with 

 cover exceeding 1% include Artemisia f rigida , Opuntia 

 polyacantha . Aqropyron spicatum , and Oryzopsis hymenoides . 



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