Astragalus gilviflorus has large cream to yellowish flowers, sometimes with 

 purple etching. It is found tliroughout the Ashland District and much of 

 Montana. 



A. hyalinus has cream to whitish flowers that are typically larger than those of 

 A. barrii. The petals are quite hairy on their backs (can be seen with a hand 

 lens). It was first discovered in the state in 1976 and had been tracked as a 

 State Species of Special Concern, known only from the Prj'or Mountains. 

 Documentation of its abundance in the Pryor Mountains (Lesica and Achuff 

 1992) provided the basis for taking it off of the state list. It had not been 

 recorded from the Ashland District until the time of this study, when it was 

 documented by David Schmoller, Biological Technician with the Ashland 

 District, and verified by Matt Lavin, Montana State University (MONT). 

 Because the Astragalus barrii survey was targeted for early in the season, 

 while A. hyalinus flowered later in the season, we cannot be certain of the 

 identification of populations containing only vegetative material. This is 

 detailed in the study area distribution discussion (below). 



An unusual population of white-flowered milkvetch was found in the study 

 area. The flowers were within the size range of ^. barrii, but were white and 

 strigose dorsally and the banner petals had purple veins (Appendix E-2). In A. 

 hyalinus, the petals are cream with purplish tips, with no mention of veins 

 (Great Plains Flora Association 1986). However, populations are occasionally 

 found with veins on the banners (Matt Lavin, Montana State University, pers. 

 comm.). A summary of species characteristics is presented in Table 2. The 

 small-flowered population was characterized as being A. hyalinus by Dr. 

 Lavin, who noted that small-flowered populations oiA. hyalinus are 

 occasionally found. This size dimorphism may be attributable to moisture 

 availability. David Schmoller later found several populations of A. hyalinus 

 with normal sized flowers. 



In the study area, Astragalus hyalinus can be very similar in growth habit to A. 

 barrii, at least when it occurs in the habitat to which A.barrii is restricted. Six 

 populations in vegetative condition that were tentatively identified as A. barrii 

 during this study and in earlier surveys were subsequently determined to be A. 

 hyalinus by Schmoller (pers. comm..), who found them in flower (whether 

 these populations had small or normal sized flowers is not known). With the 

 documented presence of A. hyalinus in Badlands segments of the study area, 

 reliable identification should only be made with flowering material (Matt 

 Lavin, Montana State University, pers. comm..). Fruiting material may not be 

 reliable because A. hyalinus can have short peduncles though it typically has 

 none (Great Plains Flora Association 1986), and vegetative growth may 

 obscure peduncles in A. barrii (Marriott pers. obs.). 



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