certainly distinguished from these species when m 

 flower. However, in the field, A, barrii is 

 distinctive for its small, iridescent, bluish- 

 purple to bluish-pink flowers. Astragalus 

 gjlviflorus on the other hand, has large cream to 

 yellowish flowers, sometimes with purple etching, 

 while A. hvalinus has large white flowers with some 

 petals faintly lilac-tinged. Astragalus 

 Rericoleucus has pink-purple flowers with a paler 

 horizontal band, but the flowers are about one half 

 the size of flowers of A. barrii . The field 

 characteristics of A. barrii are most similar to A. 

 aretioides ; however, the latter has smaller flowers, 

 is more densely mat-forming, and is found at higher 

 elevations in Montana. 



D. Identifying characteristics of material which is in 

 interstate or international commerce or trade: No 

 interstate or international commerce or trade is 

 known . 



E. Photographs and line drawings: Figure 1, p. 8, is a 

 copy of an illustration that accompanied the 

 description of this species in Reel et al. (1989), 

 drawn by Debbie McNiel. The color slides (p. 9) are 

 duplicates of those taken at the sites indicated by 

 the three-digit occurrence numbers, Additional 

 slides of A. barrii and its habitat are housed at 

 the office of the Montana Natural Heritage Program, 

 Helena, Montana. 



4. Significance. 



A. Natural: Astragalus barrii is a regional endemic 

 that is known only from Southwestern South Dakota, 

 northeastern Wyoming and southeastern Montana. In 

 Montana, it is associated with the barren soils of 

 "gumbo clay" knolls, buttes and cliffs. In many 

 areas it is one of only a few species to stabilize 

 the soil surface. 



B. Human: Astragalus barrii was first collected by a 

 rancher, Claude A. Barr, who also ran a small mail- 

 order native plant nursery. He apparently sold this 

 hardy species for horticultural purposes. 



Astragalus barrii is also pertinent to the study and 

 delineation of the Orophaca phalanx, and its 

 placement within the genus Astragalus . 



