10 



REPRODUCTIVE BIOLOGY 



a. TYPE OF REPRODUCTION: The flowers of L. 

 humil is are chasmogamous (they have 

 conspicuous corollas, and open normally for 

 fertilization). Self-incompatibility is 

 widespread in the genus, though self- 

 compatibility is also present in at least 

 some species. Most populations of 

 Lesguerel la are in open habitats, with the 

 plants aggregated together. Undoubtedly, 

 cross-pollination is the norm for the genus 

 as a whole (Rollins and Shaw, 1973). In an 

 alpine species such as L. humi lis , self- 

 pollination may be more prevalent, owing to 

 the short growing season. Fruit set during 

 peak periods appeared to be very vigorous. 

 During surveys in 1987, no evidence of any 

 vegetative reproduction was observed. 



b. POLLINATION BIOLOGY: Rollins and Shaw (1973) 

 report that "(i)n the field, insects, mostly 

 bees and flies, were repeatedly observed 

 visiting the flowers" of Lesguerel la . During 

 field surveys in 1987, no insects were 

 observed visiting the few individuals of L. 

 humi 1 is which were flowering. It is unknown 

 whether there are any specific plant- 

 pollinator dependencies involving L. 

 humi lis . 



c. SEED DISPERSAL AND BIOLOGY: Each fruit of L. 

 humil is is capable of producing four seeds. 

 The seeds are wingless, and about H mm. (0.08 

 in.) in diameter (Rollins, 198^); there does 

 not appear to be any mechanism that might aid 

 in long-distance dispersal. Thus, it is 

 likely that most seeds fall near the parent 



plants. 



G. POPULATION ECOLOGY 



COMPETITIVE INTERACTIONS: Little information is 

 available regarding the competitive ability of 

 perennial alpine plant species such as L. humilis . 

 As noted previously, the species grows most 

 frequently in more open microsites within the 

 timberline and alpine areas which it inhabitats. 

 This suggests that the species would not be very 

 agressive in more densely vegetated areas. In a 

 few cases, plants were observed growing amongst 

 small mats of associated vegetation. These 

 situations may arise from the suitability of such 

 microsites for seed germination. 



