E. Photographs and line drawings: Figure 1 provides 

 copies of the illustrations of this taxon, taken 

 from Hitchcock (1950) and Hitchcock et. aL- (1969). 

 The color slides (p. 8) are duplicates of those 

 taken at the Granite Creek South site (occurrence 

 no, 002). Additional slides of the Lolo Hot 

 Springs area, and of Tr isetum wolf i i and T. 

 canescens , are housed at the MTNHP office in 

 Helena, MT . 



Significance. 



A. Natural: Though taxonomical 1 y distinct in its 

 characteristics, the evolutionary significance of 

 Tr isetum or thochaetum has been, and remains, 

 obscure. This is owing to the apparently hybrid 

 nature of the taxon, which is discussed at length 

 in the appropriate section (p. 20). The taxon 

 does not appear to have any peculiar ecological 

 adaptations or structures; nor does it have any 

 apparent obligate relationships with other 

 species, or roles in stabilizing landforms. 

 Although currently known only from a very limited 

 geographic area, it is reasonable to speculate 

 that the taxon may occur in other locales where 

 the putative parents are biotically sympatric. 

 The ranges of those two Tr isetum species ( T_. 

 canescens and T. wolf i i ) overlap in a broad area 

 over much of the Pacific Northwest (Hitchcock, 

 1950). 



B. Human: Tr isetum or thochaetum is of potential 

 scientific significance in any study of the 



b iosystemat ic relationships among congeneric 

 taxa, especially the relationships of the two 

 putative parental species. The probable hybrid 

 origin of T^. or thochaetum provides a way of 

 studying the degree of genetic divergence among 

 the related taxa. Questions addressing possible 

 polyploidy among these taxa would also be of 

 scientific interest. Otherwise, T. or thochaetum 

 has no agricultural, economic, horticultural, or 

 other currently known human uses or significance, 

 owing to its rarity and relative obscurity. 



Geographical distribution. 



A. Geographical range: Tr isetum or thochaetum is 

 known, historically and currently, only from a 

 small area in extreme southwestern Missoula 

 County, Montana, U.S.A. (Figure 2, p. 9). Two 

 previous collections (1908, 1951) were in close 

 proximity to Lolo Hot Springs (occ. no. 001). The 

 currently known sites (consisting of eight small 

 clusters) are grouped into three occurrences 

 (002-00^), all of which are in the Granite Creek 



