HABITAT: Throughout its range, silky prairie clover grows in very sandy substrates in habitats 

 ranging from dunes to sandy prairies and open woodlands (Great Plains Flora Association 1 986). It 

 occupies loose, upland sandy range sites in Montana. The Medicine Rocks population is in early 

 successional sand dune habitat in an area with little cover by ponderosa pine {Pinus ponderosa). The 

 sparse vegetation is dominated by needle-and-thread {Stipa comata). The BLM Watch species, 

 Schweinitz' flatsedge (Cyperus schweinitzii) is an associate. The Humbolt Hills site is a small 

 blowout between isolated sandstone outcrops with associated species including prairie sandreed 

 {Calamovilfa longifolia) and the BLM Watch species, narrowleaf penstemon {Penstemon 

 angustifolia) . 



SPECIES BIOLOGY: The species is a long-lived perennial that is adapted for insect pollination. It 

 is aptly named as "silky" for the dense hairs that lie flat against the leaflets that give it a silky sheen, 

 and are adaptation to its dessicating habitat. 



The Medicine Rocks population has been estimated at over 200 plants; noted in 1 992 as having 

 notable vigor and many stems. The Humbolt Hills occurrence consisted of more than 10 plants 

 begirming to flower in early June, but a complete survey was not conducted. 



OTHER COMMENTS: The Medicine Rocks population was noted as having notable vigor and 

 multiple stems in 1992, the year following wildfire. The species is palatable to livestock and is 

 generally considered to be a decreaser (Smith 1976). The Humbolt Hills population is at the edge of 

 oil field development, but the single suitable spot where it was noted was not affected by the 

 associated oil field roads and facilities. 



Survey of BLM and State land in the Humbolt Hills is needed to determine the extent of the Dalea 

 villosa populations there. It may warrant consideration as a watch species. No new information is 

 available from BLM lands out of this study so there is no basis for considering a status change. This 

 is one of several sand-loving species in the county that are often found with other species of special 

 concern where the habitat is extensive and/or in good condition. 



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