b. Specific known pollinators: The only pollinator visits observed 

 were late afternoon visits made by bumblebees {Bombus spp.), 

 selectively visiting the species at EO#001. This is also a site with 

 extensive spotted knapweed, also visited by the bumblebees. Long- 

 tongued bumblebees are the most important pollinators elsewhere in 

 its range (Sipes and Tepedino 1995). The bees are provided with 

 nectar rewards, but the pollen are in "pollinia" (pollen masses) that 

 are not available to them for food. The distinctive "coumarin" odor of 

 the species (Sheviak 1984) suggests that there may be other rewards 

 or benefits that flowers potentially offer their pollinators besides food 

 such as sources of critical chemicals, e.g., for producing pheromes 

 (after Buchmann and Nabhan 1996). 



c. Other suspected pollinators: Only bumblebees have been noted to 

 date visiting Spiranthes diluvialis flowers at one site in Montana. 

 Elsewhere, an anthophorid bee, and hawkmoth were seen in single 

 instances of also carrying the pollinaria oi Spiranthes diluvialis (Sipes 

 and Tepedino 1995). 



d. Vulnerability of pollinators: The bumblebees are vulnerable to 

 pesticides, and to land management practices that destroy available 

 nest sites. There are both above ground and below groimd nesting 

 species of bumblebees (Sipes and Tepedino 1995, Arft 1995a), and 

 the specific bumblebee pollination vector in Montana and its habitat 

 vulnerability have yet to be identified. 



3. Seed dispersal. 



a. General mechanisms: The dust-like seeds of Orchid Family 

 members are adapted to being carried by the wind (Cronquist 1968). 



b. Specific agents: NA 



c. Vulnerability of dispersal agents and mechanisms: NA 



d. Patterns of propagule dispersal: The minute seeds may be carried 

 great distances on the wind. If the capsules dehisce under cold 

 temperatures, then the prevailing dispersal winds would be north 

 winds. 



4. Seed biology. 



a. Amount and variation of seed production: Orchids have abundant, 

 tiny "dust-like" seeds. Pollinators rarely visit a flower more than once. 



36 



