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SUMMARY 



In 1989, the Lewis and Clark National Forest and the 

 Montana Natural Heritage Program entered a Challenge 

 Cost-share agreement. Under the agreement, the Montana 

 Natural Heritage Program conducted field surveys to 

 determine the distribution of Astragalus molybdenus 

 populations on Forest lands. In addition, plant 

 material was collected for morphologic and molecular 

 systematic studies to compare these populations to 

 Colorado populations, and to populations of Astragalus 

 shultziorum from western Wyoming. 



Survey efforts revealed seven new populations of A. 

 molybdenus in the Sawtooth Range, Teton County, 

 Montana. All of these populations occur within 10 

 miles of the original collection site on Mt. Wright. 

 This brings the total number of known populations in 

 Montana to eight. All of the populations were quite 

 large, although it appears that populations expand by 

 cloning through rhizome extension, rather than by ^ 

 establishment of new plants from seed. At least in 

 1989, sexual reproduction was limited to small portions 

 of most populations (the exception was at Our Lake 

 (002)). In 1990, flowering and fruiting again appeared 

 to be fairly extensive at Our Lake (002) . 



Additional surveys could reveal more populations to the 

 north or south of the known populations, in areas where 

 calcareous soils occur in alpine or very open subalpine 

 (7,000 to 8,000 ft. in elevation) habitats. 



The results of the taxonomic studies indicate that 

 there has been some evolutionary divergence among the 

 populations of Astragalus in all three states. The 

 genetic studies do not align the populations in a 

 similar pattern; while the cpDNA studies indicate a 

 close relationship between the Montana and Wyoming 

 populations, the enzyme studies suggest that the 

 Colorado and Montana populations are most similar 

 genetically. The cursory morphological studies do not 

 reveal any major differences among the three states; 

 however, the Montana and Wyoming populations do share 

 certain features of fruit morphology not found in 

 Colorado plants. Thus, from a taxonomic viewpoint, it 

 may be appropriate to recognize the populations from 

 all three states as members of one widespread species; 

 these could perhaps be distinguished as varieties, as 

 suggested by Barneby. It is important to emphasize 

 that the populations in all three states are largely 

 clonal, and may represent only one or a few genotypes 

 in each state (Lavin et al. 1990, Marriott 1990). 



