order to grow (Sahai and Shivanna 1985, 

 Macior 1980) . It is not known if this is the 

 case with C. longispica. 



4. DEMOGRAPHY: The large root crown of some plants of 

 C. longispica suggest that it is a long-lived 

 perennial. Demography studies of C. longispica 

 have not been done. 



G . ECOLOGY 



1. BIOLOGICAL INTERACTIONS 



a. PARASITISM: Castilleja longispica is a 

 hemiparasite, capable of photosynthesis but 

 obtaining a large part of the water, 

 nutrient, and even carbohydrate requirements 

 from its host (Malcolm 1966, Kuijit 1969). 

 Hemiparasites in the Scrophulariaceae are 

 generally not thought to be host specific 

 (Kuijit 1969) , and the host range of C. 

 longispica is not known. However, the fact 

 that it is always associated with moderate to 

 dense stands of Artemisia tridentata perhaps 

 suggests that this shrub is a preferred host. 



b. COMPETITION AND FACILITATION: Hemiparasites 

 that have attached to a host probably suffer 

 little direct effect from competition as much 

 of their water and nutritional requirements 

 are obtained from the host. 



c. HERBIVORY: Nearly all of the populations of 

 C. longispica in the Beartooth and Pryor 

 mountains are subject to livestock grazing. 

 Some of these sites, such as Commissary 

 Ridge, suffer heavy grazing pressure with 50- 

 75% utilization of palatable grasses. 

 Nonetheless, evidence of grazing of C. 

 longispica was not apparent at any of the 

 sites visited. Furthermore, the occurrence 

 of ungrazed clumps of grass adjacent to large 

 C. longispica plants in heavily grazed 



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