16 



2. Montana distribution: The taxon is now known from the 



foothills of the Tendoy and Pioneer Mountains (Beaverhead 

 County), the Jefferson River drainage (Broadwater, 

 Jefferson, and Madison Counties), the Rattlesnake Hills 

 (Gallatin County), the Big Belt Mountains (Lewis and Clark 

 County), and the Pryor Mountain desert (Carbon County). 



3. Occurrences in the Tobacco Roots: Delphinium bicolor ssp. 

 novum is documented from two sites in the study area, just 

 to the north and to the south of Clark Canyon Reservoir. An 

 Element Occurrence Record (EOR) and map showing the precise 

 location of the population to the south of Clark Canyon 

 Reservoir (007) are given in Appendix C. This taxon was 

 dropped from tracking by MTNHP in fall of 1994, thus an EOR 

 is not provided for the occurrence to the north of Clark 

 Canyon Reservoir, however, the approximate location is 

 mapped in Figure 2, and is at the same site as an occurrence 

 of Sphaeromeria capitata (005) for which an EOR and map are 

 provided in Appendix C. 



D. Habitat 



1. Associated vegetation: Throughout its range, Limestone 

 Larkspur occurs mostly in sparsely vegetated microhabitats 

 within sagebrush grasslands (most commonly Artemisia 

 tridentata/Elymus spicatus habitat types) and mountain 

 mahogany (Cercocarpus ledifolius) communities. Immediate 

 associates are usually other limestone adapted species 

 including at the sites around Clark Canyon Reservoir, 

 Sphaeromeria capitata, also treated in this report. Other 

 associated plants are listed in the general site description 

 fields of the EOR in Appendix C. 



2. Topography: Delphinium bicolor ssp. novum grows on 

 unglaciated ridges, slopes, rockslides, and banks in the 

 foothills and basins at low to middle elevations (4,100- 

 6,800 feet). 



3. Soil relations: The taxon is confined to soils and lithic 

 substrates derived from calcareous parent materials. In the 

 study area these are shallow, gravelly, fine textured soils 

 on top of limestone bedrock. Along the Jefferson River they 

 are loose, rich soils. In the Pryor Mountain Desert they 

 include dry, calcareous sands, and in the Big Belt Mountains 

 the plant grows in loose limestone talus. These soils are 

 usually moist only in the spring and early summer when the 

 plants are actively growing. 



E. Population demography and biology 



1. Demographic details: The occurrences in Montana range from 

 a single plant to thousands of plants covering hundreds of 



