32 



found. During surveys by the author in 1986, 

 1987, and 1989, no evidence of any vegetative 

 reproduction was observed. 



2. Pollination. 



a. Mechanisms: As described above, Penstemon 

 lemhiensis appears to be an obligate out- 



crosser; the primary mechanism is via 

 insect pollination. 



b. Specific known pollinators: During 

 observations of insect visitors to P. 

 lemhiensis at the Big Hole National 

 Battlefield, 13 insects that made contact 

 with some part of the flowers were 

 collected (Ramstetter 1983) . Of these, 

 two species, Pseudomasaris vespoides and 

 Osmia brevis , were thought to be the most 

 important pollinators. Pseudomasaris 

 vespoides is a pollen-collecting vespid 

 wasp; these wasps have long bodies, and 

 during flower visits they completely enter 

 the corollas. They were not observed to 

 visit flowers of any other plants. 

 Ramstetter (1983) concluded that •' (i)f P^. 

 vespoides is as constant to Penstemon 

 lemhiensis as my observations indicate, 

 the wasp may be an especially important 

 pollinator." Osmia brevis belongs to the 

 mason bee family (Megachilidae) , whose 

 members are known to be efficient 

 pollinators (Essig 1958) . During surveys 

 by the author in 1986, 1987 and 1989, the 

 vespid wasp was by far the most frequently 

 observed insect visitor to P. lemhiensis . 



c. Other suspected pollinators: Unknown. 



d. Vulnerability of pollinators: Unknown, 

 but the primary pollinators ( Pseudomasaris 

 vespoides . Osmia brevis ) may be vulnerable 

 to management practices such as herbicide 

 and insecticide spraying. Impacts to 

 these insects, especially P. vespoides , 

 may have a detrimental effect on seed set 

 in Penstemon lemhiensis . 



3. Seed dispersal. 



a. General mechanisms: The seeds of P. 



lemhiensis have no appendages that might 

 aid in long-distance dispersal; they are 



