C. HABITAT 



The species is found over a broad elevation range, from the 

 sagebrush zone to alpine (Dorn 1984) . The one population 

 which was surveyed in the Tendoys occurred on rolling hills in 

 shallow gravelly soil on limestone bedrock (slide 4, Appendix 

 E) . Common associates included Artemisia frigida, Oxytropis 

 lagopus, Oryzopsis bymenoides, Koeleria cristata, Penstemon 

 aridus and Penstemon eriantherus . Lesica found the species in 

 grasslands and steppe communities on gravelly, limestone 

 derived soils, on ridges and warm slopes. 



D. POPULATION BIOLOGY 



The population in the northern foothills was dense and 

 extensive, consisting of thousands of plants, occurring in 

 patches, over at least 50 acres. Many populations were seen 

 elsewhere in the range but not surveyed because the species 

 was found to be so common. 



E. MANAGEMENT CONSIDERATIONS 



Due to its abundance in the Tendoys and its relatively broad 

 distribution in Beaverhead County, we recommend that A. kingii 

 be dropped from further BLM consideration and state tracking. 



Astragalus species 

 MilXvetch 



Five species of Astragalus found in the study area were 

 among the target species, so a description of the genus is 

 given here to avoid duplication in the individual synopses. 

 Commonly called milk vetches or locoweeds, plants of this 

 extremely diverse genus belong to the Fabaceae (bean or pea 

 family) . The family (at least in Montana) is distinguished by 

 their fruit type, a legume, their zygomorphic corollas, and by 

 their usually compound stipitate leaves. The genus Astragalus 

 has a perianth which consists of five fused sepals and a 

 corolla which includes a banner (the top segment) , a keel (the 

 boat shaped bottom segment) , and two wings (the side 

 segments). There are ten stamens, nine connected in a group 

 and one free, and a single ovary which develops into a several 

 seeded, bean-like fruit. All of the MPSSC in the study area 

 have pinnately compound leaves. Species of Astragalus 

 resemble some species of Oxytropis and Hedysarum. Oxytropis 

 has a beaked keel and flowers usually borne on leafless stalks 

 unlike Astragalus with leafy flowering stems. The fruit of 

 Hedysarum is a loment, a special kind of legume which is 

 contracted and dehices between the seeds, and the keel is 

 usually longer than the banner and wings, in contrast to 

 Astragalus with shorter keels. The species of Astragalus are 

 distinguished by differences in their stipules, leaves, 

 flowers, and fruits. 



