15 



Phyllodoce qlandulif lora (Yellow 



mountain-heath) 

 Pinus albicaulis (White-bark pine) 

 Sedum lanceolatum (Lance-leaved 



stonecrop) 

 Smelowskia calycina (Alpine smelowskia) 

 Veronica cusickii (Cusick's speedwell). 



4. Dominance and frequency of the taucon: The 



total rangewide population size of 

 Lesquerella humilis is about 2400 plants, 

 divided among three populations of 900, 800, 

 and 700 plants each. The plants are 

 generally sparsely distributed. Canopy cover 

 of the populations is low and they occur in 

 plant communities which also have low total 

 cover. 



5. Successional phenomena: Lesquerella humilis 

 occurs in open communities that are 

 relatively stable. Although these 

 communities may be regarded as early 

 successional, change will be slow over the 

 next several decades and will not likely 

 affect habitat suitability for L. humilis for 

 a long time. Climatic change, such as global 

 warming, or other changes that would increase 

 vegetation cover on these sites, would 

 probably affect the populations negatively. 



6. Dependence on dynamic aspects of biotic 

 associations and ecosystem functions: 

 Unknown . 



7. Other endangered, threatened, rare, or 

 vulnerable species occurring in habitat (s) of 

 this taxon: The following species occur in 

 the vicinity of the St. Mary Peak site (001) 

 for Lesquerella humilis in the Bitterroot 

 Mountains: 



Bryoria subdiverqens (Dahl) Brodo & D. 

 Hawksw.- a lichen listed as "imperiled 

 globally" (G2) and "critically imperiled 

 in Montana" (SI) by the Montana Natural 

 Heritage Program (Shelly 1990) . 



Draba daviesiae (C.L. Hitch.) Rollins 

 and Penstemon f lavescens Pennell - both 

 are of limited geographic distribution 

 in Montana. They were formerly species 

 of special concern in the state. 



