2. Montana distribution: Known only from one site in the 

 Tendoy Mountains, Beaverhead County. 



3. Occurrences in the study area: The study area population 

 is the only one known in the state, located in the 

 southwestern part of the study area along upper Big Sheep 

 Creek. This occurrence was discovered by Peter Lesica in 

 1985. Despite intensive surveys of talus habitats in the 

 Tendoys by this project, no other populations have been found. 



C. HABITAT 



The species grows at middle to high elevations in dry, rocky 

 places, often on talus (Cronquist et al. 1984). In the 

 Tendoys the population is on dry, steep, generally southern 

 exposed slopes of loose, relatively fine, limestone talus at 

 6,800-7,200 ft, elevation (see slide 1 in Appendix E) . Soil 

 development on the talus is minimal, however, where the banks 

 have been cut by quarrying, some horizontal zonation can be 

 seen; fine particles have been weathered and leached from the 

 surface layer and deposited at depths. These clays were quite 

 moist in June and July, 1993 (a wet season) . Other plants 

 growing on these mostly barren slopes include Phacelia hastata 

 and Oenothera caespitosa. Woody vegetation on slightly more 

 stable adjacent talus includes Artemisia tridentata, 

 Chrysothamnus nauseosus, Juniperus communis, and Potentilla 

 fruticosa. Three other Montana Plant Species of Concern which 

 occupy the site are the annuals Hutchinsia procumhens , Mimulus 

 suksdorfii and Phacelia incana , which are mostly confined to 

 spots with a surface accumulation of litter, often under 

 sagebrush . 



D. POPULATION BIOLOGY 



The population is large with two subpopulations . The main 

 roadside population is quite dense in places with A. cusickii 

 the most common plant in its habitat, while the subpopulation 

 to the east consists of scattered plants. Vegetative 

 reproduction is probably common. Plants were flowering in 

 June. 



E. MANAGEMENT CONSIDERATIONS 



The fine talus of the main population has been quarried in the 

 past for use as road material in at least 4 locations 

 (Vanderhorst 1993). Although removal of material by the state 

 and BLM has been curtailed in recent years, illicit quarrying 

 has probably continued to a limited extent. Plants are 

 generally absent from the disturbed slopes but in a few spots 

 have become re-established. The plants seem more tolerant of 

 disturbance on level ground and have colonized the bottoms of 

 the quarried areas and the roadside. A monitoring program was 

 established this past summer to document further disturbance 

 to the site and to study recolonization of the quarries by A. 

 cusickii (Vanderhorst 1993). It is recommended that this site 



