> 



31 



Big Hole National Battlefield (006), 

 Ramstetter (1983) found that, in 1982, flower 

 buds began to develop by 12 June, and plants 

 were in bloom by 27 June; all flowers in an 

 inflorescence opened within three to five days. 

 In 1983, most inflorescences at Argenta (001), 

 Badger Pass (005) , and Lemhi Pass (003) had 

 dropped their flowers, and fruits were 

 developing, by 23-26 July; at the Battlefield, 

 most flowers had dropped, but no developing 

 fruits were seen. Ramstetter (1983) 

 additionally states that " (o)bservations made 

 in 1982 and 1983 indicate that the sexual 

 reproductive period at higher elevations is 

 somewhat shorter than at lower elevations." In 

 1986, the peak blooming period at the high- 

 elevation sites in the northeastern Pioneer 

 Mountains (Quartz Hill Gulch (010) , Echo Gulch 

 (011)) had just begun on 8 July, indicating 

 that the peak reproductive period is later at 

 these sites. 



2. Relation to climate and microclimate: As 



mentioned, plants on warmer exposures may begin 

 flowering earlier in the growing season. 



D. Reproductive ecology. 



1. Types of reproduction: The flowers of P. 



lemhiensis are protandrous (the anthers dehisce 

 before the stigma is receptive) ; anthers begin 

 to shed pollen approximately two days before 

 the stigma becomes sticky and receptive 

 (Ramstetter 1983) . 



Breeding system studies conducted at the Big 

 Hole National Battlefield suggest that P. 

 lemhiensis is an obligate out-crosser 

 (Ramstetter 1983) . Plants with flowers that 

 were not manipulated (control) yielded an 

 average of 17.80% mature seed set. In 

 comparison, plants cross-pollinated by hand 

 yielded an average of 22.51% mature seed set, 

 significantly higher than the average for the 

 control plants. Thus, seed set may be somewhat 

 limited by the level of insect pollination. 

 Obligate out-crossing was further suggested in 

 plants that were self-pollinated by hand; an 

 average of only 2.10% mature seed set was 

 obtained. However, open-pollinated flowers 

 whose anthers were removed initiated an average 

 of 17.29% seed set. Little evidence of 

 agamospermy (asexual seed production) was 



