56 



GEOGRAPHICAL DISTRIBUTION 



Global distribution: Common in eastern Nevada and western Utah and also known 

 sporadically from northeastern Utah, northwestern Colorado, Wyoming, and central 

 Idaho (Cronquist et al. 1984) to southwestern Montana. 



Montana distribution: Southwestern Beaverhead County, including four records 

 around the periphery of the Tendoy Mountains and two in the Grasshopper Study Area 

 (Figure 23). 



Grasshopper distribution: Bannack and Clark Canyon Reservoir areas (Figure 23). 



HABITAT: Cronquist et al. (1984) describe the habitat as "stony, often calcareous slopes." 

 Within the study area, P. incana grows on dry limestone ridges, often in fine soils below rubble, 

 especially in small accumulations of leaf litter below mountain mahogany. Its elevations in the 

 Study Area range from 6050-6200 ft, while it has been documented at 7080 ft. elsewhere in the 

 state. 



Dominant woody vegetation on these slopes is Cercocarpus JedifoUus, often \\\\\\ Artemisia 

 tridentata (Appendix D-21). It typically grows beneath these shrubs. A representative list of 

 associated species include: 



Agropyron spicatwn 

 Chenopodiwn 

 Collinsia parviflora 

 Cryptantha watsonii 

 Descurainia richardsonii 

 Malacomia africana 

 Oryzopsis hymenoides 

 Phacelia has tat a 

 Phacelia linearis 



In the Tendoy Mountains, it was also associated with four other restricted calciphilic species: 

 Agastache cusickii, Hutchinsia procumbens, hdimulus suksdorfii, and Stanleya viridiflora 

 (Vanderhorst and Lesica 1994). 



POPULATION INFORMATION: The t\vo populations discovered in 1995 ranged in 

 estimated numbers from 200 to >1000 plants. The Bannack population was recun-ent in separate 

 subpopulations, while the Clark Canyon Reser\'oir population seemed restricted to a single area 

 <5 m^, suggesting that it may have recently become established. The largest known population is 

 in the Tendoy Mountains on BLM land and approaches or exceeds 10,000 plants. 



As an amiual, its numbers would be expected to vary greatly from year to year. In general, its 



