38 



Astragalus argophyllus Nutt. var. argophyllus 



Four new Centennial Valley populations were found of Astragalus 

 argophyllus var. argophyllus , almost doubling the local number of 

 populations. Included among these was one of the largest known 

 populations at over 1000 plants, in T.14S R.5W Sec. 30 NW 1/4 on 

 BLM lands. These results underscore the interpretation made in 

 the Tendoy Mts . sensitive plant survey that this species is 

 relatively widespread in southern Beaverhead Co. , MT (Vanderhorst 

 and Lesica 1994). Its habitat is often heavily used by cattle, 

 but the species does not appear to show major decline under 

 livestock grazing. For these reasons, it has been recommended 

 that it be dropped from further consideration by the BLM and the 

 Montana Natural Heritage Program. 



It occupies wet, alkaline meadows associated with plants such as 

 Juncus^ balticus . Poa nevadensis . Artemisia tripartita . Iris 

 missouriensis and others. These are not shown on the Figure 2 

 map. 



Astragalus lentiginosus (Rydb.) Peck var. salinus 

 Howell) Barneby 



Three new Centennial Valley populations were found of 

 Astragalus lentiginosus var. salinus along the north side of the 

 valley. These results underscore the interpretation made in the 

 Tendoy Mts. sensitive plant survey that this species is 

 relatively widespread in southern Beaverhead County, MT 

 (Vanderhorst and Lesica 1994). Some of its populations in this 

 other study are extremely large and had no apparent threats. For 

 this reason, it has been recommended that it be dropped from 

 further consideration by the BLM and the Montana Natural Heritage 

 Program. 



It occupies sagebrush habitat on sandy or clayey soils. Its 

 Centennial Valley habitat is dominated by Artemisia tridentata or 

 Agropyron spicatum with Festuca idahonis or Festuca scabrella . 

 Other associated species include Lupinus sericeus , Bromis 

 inermis , and Haplopappus acaulis. These are not shown on the 

 Figure 2 map. 



