Occurrence : This species is common in tundra habitats in the 

 East Pioneer Range of Beaverhead County. It also occurs in the 

 Tobacco Root Range. The only sites in the Beartooth Mtns . are 

 from the west end of the Line Creek Plateau; however, it likely 

 occurs in other areas as well. 



SENECIO AMPLECTENS Gray var. HOLMII (Greene) Harr. (Clasping 



groundsel) [G4T7/S1] 

 Geographic Range : Beartooth Mountains of Montana, south to 

 Nevada and New Mexico. 



Habitat : Talus slopes of the alpine and subalpine zones. 

 Occurrence : The only known location for this species in Montana 

 is on slopes of the Line Creek Plateau. The population is on a 

 steep slope, so the extent and number of plants are not known. 

 Additional populations may occur on nearby inaccessible slopes. 



STELLARIA CRASSIFOLIA Ehrh. (Thick-leaved chickweed) [G4/S1] 



Geographic Range : Circumboreal , south in western North America 

 to Montana, Idaho and Colorado. 



Habitat : Moist or wet meadows and tundra in the montane to 

 alpine zone. 



Occurrence : This plant has been collected once in the Centennial 

 Valley of Beaverhead County and once on the Line Creek Plateau in 

 the Beartooth Mtns. It is very similar to the widespread S. 

 longipes . The collection made by botanists working for 

 Bitterroot Native Growers in 1991 were in fruiting condition and 

 could not be identified positively. All Stellaria s I found on 

 the Line Creek Plateau during 1993 surveys appeared to be S_=_ 

 longipes . Conseguently , the distribution of this species on the 

 Line Creek Plateau is not known. 



THLASPI PARVIFLORUM A. Nels. (Small-flowered pennycress) [G3/S2] 



Geographic Range : Central Idaho, northwest Wyoming and southwest 



Montana. 



Habitat : Moist to dry meadows and limestone cliffs in the 



montane to alpine zones. 



Occurrence : Known populations of this species are generally 



small; the plant occurs sporadically in small colonies throughout 



large areas of apparently appropriate habitat. At least six 



colonies are known from the Line Creek Plateau. 



Physical and Climatic Conditions 



Geology 



The Beartooth Mountains are a large uplifted fault block of 

 precambrian crystalline rock, trending from southeast to 

 northwest. Most of the rocks are gneisses; however, small 

 amounts of other types of metamorphosed granitics also occur (Alt 

 and Hyndman 1986) . The Line Creek Plateau is the easternmost 



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