11 



B. 



nature of the populations, and their intrinsically 

 small size, may predispose many of them to extirpation. 



Of these 16 new populations, 

 disturbed roadbanks (007, 02 

 034, 035, 036); the size of 

 ranged from two to 74 plants 

 indicate that P. lemhiensis 

 colonize disturbed habitats, 

 abundance in these unnatural 

 roadside populations should 

 ephemeral, as such habitats 

 maintenance activities (road 

 spraying, etc. ) . 



ten were found along 

 4, 027, 028, 029, 032, 033, 

 these roadside populations 

 Although these findings 

 has some ability to 



it is never found in 



situations. These 

 be considered very 

 are subject to frequent 



grading, herbicide 



The six new populations that occur in native habitats 

 (004, 023, 025, 026, 030, 031) range in size from four 

 to 110 plants. Three of these six populations are in 

 areas that have been seriously impacted by exotic weed 

 invasion. The two native sites in Ravalli County have 

 been especially impacted by Centaurea maculosa (spotted 

 knapweed). In one case (Spring Gulch (030)), the 

 population consisted of only four plants in 1989; it is 

 possible that knapweed is causing the extirpation of 

 this population. 



MANAGEMENT RECOMMENDATIONS: Land ownership for the 

 populations discovered in 1989 is as follows 

 (BT=Bitterroot National Forest; BV=Beaverhead National 

 Forest) . Print-outs providing details on these sites 

 are provided on pp. 25-38. 



All appropriate Beaverhead and Bitterroot National 

 Forest personnel should be notified of the populations 

 currently found on U.S. Forest Service lands. This is 

 especially important for personnel involved in road 

 maintenance and weed control activities. 



