13 

 III. LITERATURE CITED 



Achuff, P.L. 1991. Plant species of special concern in Montana. 

 Montana Natural Heritage Program, 1515 E. 6th Ave., Helena, 

 MT. 2 pp. mimeo. 



Alt, D., and D.W. Hyndman. 1986. Roadside Geology of Montana. 

 Mountain Press Publishing Company, Missoula, Montana. 427 

 pp. 



Cronquist, A. 1991. Letter of 11 March to Lisa Schassberger , 

 Montana Natural Heritage Program, Helena, Montana, 

 concerning annotation of Cirsium specimens from the Little 

 Belt Mountains, Montana. 



Cronquist, A. 1992. Letter of 13 January to Lisa Schassberger 

 Roe, Montana Natural Heritage Program, Helena, Montana, 

 concerning annotation of Cirsium specimens from the Little 

 Belt, Castle, and Sawtooth Mountains of Montana. 



Massey, J.R., and P.D. Whitson. 1980. Species biology, the key 

 to plant preservation. Rhodora 82:97-103. 



Palmer, M. 1987. A critical look at rare plant monitoring in 

 the United States. Biological Conservation 39:113-127. 



Schassberger, L.A. 1991. Report on the conservation status of 

 Cirsium lonqistylum . a candidate threatened species. 

 Montana Natural Heritage Program, Helena, Montana. 92 pp. 



Schassberger, L.A., and P.L. Achuff. 1991. Status review of 

 Cirsium lonqistylum . U.S.D.A. Forest Service, Region 1, 

 Lewis and Clark National Forest. Montana Natural Heritage 

 Program, Helena, Montana. 78 pp. 



U.S. Department of the Interior. 1990. Endangered and 



threatened wildlife and plants; review of plant taxa for 

 listing as endangered or threatened species; notice of 

 review. Federal Register 50 CFR Part 17: 6184-6229. 



