12 



C. Geographic distribution 



1. Species range: The taxon appears to be endemic to Montana. 



2. Montana distribution: Seven populations are known, all in 

 Beaverhead County, mostly in the foothills of the Pioneer 

 Mountains and south around Badger Pass and Bannack, but a 

 single outlying population is in the Centennial Mountains. 



3. Occurrences in the study area: A population was found in 

 1992 by Bonnie Heidel on the ridge overlooking Hangman's 

 Gulch and the occurrence was relocated in 1994. The 

 population is on BLM land entirely outside of the present 

 Bannack State Park boundaries, but within the boundaries of 

 the current Recreation and Public Purposes Patent 

 application. An Element Occurrence Record and topographic 

 map showing the precise location are given in Appendix D. 



D. Habitat 



1. Associated vegetation: Lesquerella sp. novum I occurs in 

 both the foothill and sub-alpine zones (Heidel 1993). The 

 population at Bannack is in a foothill setting in a 

 community dominated by mountain mahogany ( Cercocarpus 

 ledifolius ) and bluebunch wheatgrass ( Elymus spicatus ) . 

 Douglas fir ( Pseudotsuga menziesii ) and Rocky Mountain 

 Juniper ( Juniperus scopulorum ) are two subdominant woody 

 species at the site. The undescribed bladderpod usually 

 grows in the most open and exposed microhabitats, rarely 

 close to or in the shade of the dominant canopy species 

 (Heidel 1993). Other forbs in these openings include Allium 

 textile , Arenaria kingii , Castilleja pallescens , Haplopappus 

 acaulis , Mimulus suksdorf ii , Penstemon aridus, and another 

 Montana plant species of special concern, Lomatium 

 attenuatum . 



2. Topography: The foothills sites in Beaverhead County are on 

 ridges and upper slopes on topography controlled by outcrops 

 of relatively erosion resistant Madison limestone (Heidel 

 1993). The elevation of these sites ranges from 5,600 to 

 7,440 feet. At Bannack, the population is on westerly 

 facing slopes below the ridge overlooking Hangman's Gulch, 

 at elevations between 6,300 and 6,400 feet. 



3. Soil relations: The soils of most population sites are 

 derived from calcareous formations of the Madison Group 

 (Heidel 1993). The population locations and boundaries in 

 general seem strongly controlled by edaphic substrate. The 

 soil at the Bannack site is a shallow, gravelly clay derived 

 from loose limestone scree. 



