the Beaverhead National Forest in the Tendoys (Vanderhorst 1995a) and to the north on BLM 

 land in the drainage of Grasshopper Creek (Heidel and Vanderhorst 1996, Vanderhorst 1995b). In 

 1 996 the species was found by Bonnie Heidel on BLM land in the Ruby Range, the first 

 occurrence documented in Madison County. There are now a total of nine occuiTences known in 

 Montana (see state distribution map). 



Local distribution: One population was documented in the study area in Laurin Canyon 

 on the northeast flank of the Ruby Range. It is present in at least two openings on the 

 lower south facing slopes of the lower 1/2 mile of the canyon. The species was not seen 

 during June surveys in canyons on the west and southeast flanks of the Ruby Range, and 

 it was not possible to conduct a complete survey in July because the plant was 

 inconspicuous after flowering and was beginning to dry. 



HABITAT: Lomatium attenuatum grows on sparsely vegetated slopes in dry, poorly developed 

 lithosols derived from limestone or volcanic parent materials. All but one Montana population, 

 including the Ruby Range occun'ence, are in soils derived from limestone. The substrates usually 

 have a high fraction of gravel and are well drained, unstable, and easily disturbed. Larger 

 populations extend over all aspects and slope positions but over a half of the known Montana 

 occuiTences including the one in the Ruby Range are confined to southerly aspects. Elevations 

 range from 5,700 to 8,700 feet. 



Vegetation on most of these slopes is a patchy mosaic of evergreen tree and slirub communities 

 with openings occupied by scattered bunchgrasses and forbs. The habitats are commonly 

 dominated by Pinus flexilis (limber pine), Pseudostuga menziesii (Douglas fir), or Cercocarpus 

 ledifoUus (mountain mahogany), and Agropyron spicatum (bluebunch wheatgrass) is usually the 

 dominant bunchgrass. A few sites are big sagebrush {Artemisia tridentata subsp. vasyand) or low 

 sagebrush {A. nova) communities or are larger openings with few closely associated woody 

 species present. At several sites, Lomatium attenuatum grows with other BLM Sensitive or 

 Watch species adapted to dry, limestone derived slopes, such as LesquereUa pulchella, Phacelia 

 incana, and Sphaeromeria argentea, but these species were not found in the Ruby Range. 



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