measures of genetic variation (Brown 1990) . 

 Three of the seven enzymes studied did reveal 

 patterns indicating that the Colorado and 

 Montana populations are more similar to one 

 another than either is to the Wyoming 

 populations. The results also suggest the 

 possibility of polyploidy (duplication of the 

 full sets of chromosomes, resulting in higher 

 chromosome numbers) , again especially in the 

 Colorado and Montana populations. Chromosome 

 counts would be very useful in further 

 clarifying the evolutionary relationships 

 within the A. molybdenus - shultziorum complex. 



d. DISCUSSION: The results of each of these 

 studies indicate that there has been some 

 evolutionary divergence among the populations 

 of Astragalus in all three states. This 

 divergence is undoubtedly related to the 

 large geographic distances separating them. 

 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. 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. These 

 populations are slowly diverging owing to the 

 large present-day geographic gaps, and 

 subsequent lack of interbreeding, between 

 them. 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) . The extensive vegetative 

 reproduction, and relatively low observed 

 rates of sexual reproduction, probably 

 account for the low levels of genetic 

 variation between populations within each 

 state. These reproductive characteristics 

 would also promote genetic differentiation 

 between populations among the states (Lavin 

 et al. 1990) . 



