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DISCUSSION 



Although the occurrences of Montana plant species of special 

 concern discussed in this report are mostly outside of the 

 present boundaries of Bannack State Park, and none are in the 

 proposed project areas, there are opportunities for the park to 

 help conserve populations of four rare plant species, and a high 

 quality and diverse native plant community. Populations of three 

 species discussed in depth in this report ( Lesquerella species 

 novum I, Lomatium attenuatum , and Sphaeromeria argentea) lie 

 within the boundaries of the Recreation and Public Purposes 

 Patent which has been applied for by the park. Several species 

 which were previously tracked by the Montana Natural Heritage 

 Program (Arenaria kingii . Delphinium bicolor ssp. novum, Mimulus 

 suksdorfii , Pediocactus simpsonii , Townsendia spathulata ) also 

 grow on the limestone hillside which hosts these species of 

 special concern. The occurrence of so many limestone adapted 

 species at one Montana site is phenomenal and rivals the riches 

 in gold which were taken from the same geological formation in 

 Bannack 's boom days. The plants, however, are potentially longer 

 lasting. Approval of the patent application could help insure 

 that future mining, or other human activity, does not threaten 

 this high quality botanical site. 



The Montana plant species of special concern discussed in 

 this report are of two kinds. The species which occur on 

 limestone ( Lesquerella sp. novum I, Lomatium attenuatum , and 

 Sphaeromeria argentea ) are characterized by having relatively 

 large populations which are confined to a particular edaphic 

 substrate. The reproductive levels of these species may be quite 

 high, and the populations seem to fill much of the potential 

 habitat. The species are rare because they grow in an unusual 

 habitat. Because the area of the Madison limestone is limited, 

 and the formation is often associated with deposits of economic 

 minerals such as gold (or the limestone itself), these habitats 

 are most threatened by mining. The open plant communities they 

 support may also be especially vulnerable to invasions of noxious 

 weeds . 



Astragalus scaphoides is a different kind of rare plant. It 

 is a regional endemic which grows in sagebrush grasslands, 

 usually in Artemisia trident at a /Elymus spicatus habitat types. 

 These are probably the most common vegetation types in Beaverhead 

 County. Astragalus scaphoides grows in soils derived from 

 various parent materials. There seems to be abundant potential 

 habitat for the species but it is found in only a small 

 percentage of this habitat. Its rarity stems from its low 

 reproductive success, and probably from the impacts of cattle 

 grazing. Populations of the plant are usually small. Penstemon 

 lemhiensis is another sensitive species known from nearby which 

 shares these attributes. Because both of these species are 

 large, upright herbaceous perennials which are palatable to 



