28 



3. Diagnostic characters: Sphaeromeria capitata differs from 

 Sphaeromeria argentea by having more dense clusters of 

 flower heads and more deeply lobed leaves. 



B. Current legal or other formal status 



1. Federal 



a. Bureau of Land Management: none 



b. U. S. Fish and Wildlife Service: none 



c. U. S. Forest Service: none in Region 1; Sensitive in 



Region 4, the Intermountain Region (U.S.D.A. Forest 

 Service 1994b) . 



2. State: The Montana Natural Heritage Program ranks 

 Sphaeromeria capitata G3 and S2S3 (Heidel 1994). This means 

 it is somewhat vulnerable globally and slightly more so in 

 Montana due to its restricted range. 



C. Geographic Distribution 



1. Species range: Widespread in Wyoming (Dorn 1992, Fertig 

 pers. commun.), but peripheral and local in Colorado (Weber 

 1987) and Montana, and disjunct in southcentral Utah (Welsh 

 1987) . 



2. Montana distribution: Carbon, Custer, and Beaverhead 

 Counties. 



3. Occurrences in the study area: One population was surveyed 

 in 1993 in the foothills just south of Clark Canyon 

 Reservoir (004) and in 1994 the species was found in the 

 foothills to the north of the reservoir (005). Element 

 Occurrence Records and maps showing precise locations of the 

 populations are given in Appendix C. 



D. Habitat 



1. Associated vegetation: Other plants which inhabit the 

 mostly barren rock outcrops where Sphaeromeria capitata 

 grows around Clark Canyon Reservoir include Artemisia 

 frigida, Erigeron compositus , Haplopappus acaulis, Koeleria 

 macrantha , Lesquerella alpina, Petrophyton caespitosum, and 

 Delphinium bicolor ssp. novum (discussed separately in this 

 report). The rock outcrops are in broader settings of 

 sagebrush grasslands and mountain mahogany communities. 



2. Topography: Sphaeromeria capitata grows on sedimentary 

 bedrock outcrops in the foothills around Clark Canyon 

 Reservoir, on ridge crests at around 6,000 feet. 



