Big Sheep Creek drainage in the southern part of the study 

 area. 



Barneb™escribes the habitat for var. salinus as "sagebrush 

 plains valleys and foothills, in sandy or clayey soils, 

 somet!;es on dunes, on alkaline playas with Sarcobatus and 

 Atlipllx, or in foothill washes." Within the study area 

 popila?ions were found at elevations ranging from 6,000 to 

 ? 000 ft on dry slopes and benches dominated by sagebrush 

 (Artemisia tridentata) or rabbitbrush (Chrysothamnus 

 nauseosus) and bluebunch wheatgrass (Agrropyron spicatum) . 



D, POPULATION BIOLOGY . ^ v, i ^ 



TWO of the populations are small with estimated numbers less 

 Slan 100 plants. The other three are quite large with between 

 1 000 and 10,000 estimated individuals each. The large 

 population south of Bell Canyon covered over 100 acres at many 

 aspects, and had many plants with mature fruits. One 

 population visited in early June was flowering, ^ut not yet in 

 fruit; both flowers and mature fruits were seen at populations 

 visited later in June and July. 



E. MANAGEMENT CONSIDERATIONS 



A. lentiginousus is of limited distribution m southern 

 Beaverhead County. Some of the populations m ^^e study area 

 are quite large. We recommend that it be dropped from further 

 BLM consideration, but it may be appropriate for recognizing 

 as a limited distribution species m Montana. 



Astragalus leptaleus Gray 

 Park mil)cvetch 



A. DESCRIPTION . , „^ q n 



1. General description: See the genus description (page 9) . 



The plants have low, inconspicuous foliage arising from long 

 rhizome-like caudex branches. 



2. Diagnostic characters: The following combination of 

 characters distinguishes this species from other Astragalus in 

 Montana (adapted from Dorn 1984): 



Perennial with stems arising from buried points of 



renewal 



Leaflets 5 or more, all jointed to the rachis 

 Stipules united on side of stem opposite petiole 

 Hairs attached at base 

 Racemes with less than 6 flowers 



Banners less than 14 mm long, keel 5.5-7.5 mm long 

 Pods unilocular, not thick wooly-hairy, not inflated, 



without a stipe, obcompressed, pendulous 



12 



