56 



1. Herbivores, predators, pests, parasites and 

 diseases: Predation of flowers and fruits by 

 caterpillars was observed during pollination 

 studies, and is likely to be a source of seed 

 loss (Lesica, 1988) ; see Appendix D, p. 71. 

 Also, although not apparently directly grazed 

 by cattle, populations of S. spaldingii appear 

 to be influenced by them indirectly through the 

 loss of native grasslands. 



2. Competition. 



a. Intraspecific: Individual plants of S. 

 spaldingii appear to be widely distributed 

 within populations, and there is no 

 evidence of competition between plants. 



b. Interspecific: Populations of S. 

 spaldingii have not been found in 

 otherwise suitable habitats where the 

 native vegetation has been displaced by 

 exotic weedy species. This species may be 

 unable to compete with aggressive weedy 

 species which have supplanted the native 

 vegetation; alternatively, the lowered 

 moisture content of the soils where the 

 native grasses have been supplanted may 

 hinder seed germination and establishment 

 of S. spaldingii plants. 



Hybridization. 



1. Naturally occurring: This species has 

 been described as an "unquestionably well- 

 marked species" (Hitchcock et ai. , 1964). 

 However, several collections at sites in 

 Oregon, on the edge of its range, have 

 larger flowers and petal blades, and later 

 flowering dates; overall, they appear more 

 similar to S. oregana . There is the 

 possibility that hybridization is 

 occurring in these peripheral populations 

 (Jimmy Kagan, Oregon Natural Heritage 

 Program, pers. comm.). 



2. Artificially induced: None known. 



3. Potential in cultivation: Plants are 

 currently being maintained in a greenhouse 

 at the University of Montana, Missoula 

 (Peter Lesica, pers. comm.). 



