other hybrids, the habitat requirements of S. x 

 pyramidata fall between those of the suspected 

 parental types (Ball et al. 1983). 



4. REGIONAL CLIMATE: The mountains of northwestern 



Montana are dominated by a cool temperate climate. 

 The weather collection site at Trout Creek Ranger 

 Station is approximately 15 miles east of the Bull 

 River valley, and at an elevation of 2,370 feet. 

 The S. X pyramidata site is at 2,300 feet in 

 elevation. For the period from 1951-1980, the 

 July mean temperature at Trout Creek Ranger 

 Station was 65.0° F, the January mean was 24.1° F, 

 and the mean annual precipitation was 30.49 inches 

 (U.S. Department of Commerce 1982) . 



F. POPULATION DEMOGRAPHY AND BIOLOGY 



1. PHENOLOGY: The Bull River Campground (001) 

 population flowers during late July. Hitchcock et 

 al. (1955-1969) state that flowering and fruiting 

 in S. X pyramidata populations occurs from June 

 through August. 



2. POPULATION SIZE AND CONDITION: The observed 

 number of stems at Bull River Campground was low 

 (three) , but the plants appeared to be in good 

 condition. 



3. REPRODUCTIVE BIOLOGY 



a. TYPE OF REPRODUCTION: Specific aspects of 

 sexual reproduction are not known. 

 Observations of populations in Washington and 

 British Columbia revfealed only one population 

 where introgression and backcrossing had 

 occurred. Reasons for the degree of 

 sterility with the putative parental types 

 are not known. This perennial does spread 

 easily via a strong rhizome system (Hess 

 1969) . 



b. POLLINATION BIOLOGY: Not known. 



c. SEED DISPERSAL AND BIOLOGY: Not known. 



G. POPULATION ECOLOGY 



1. BIOLOGICAL INTERACTIONS 



a. COMPETITION: The establishment of this 



species appears to depend on disturbance. It 



