3 



rarely streaked), 6-9 mm. (0.24-0.39 in.) long, 

 oblong in outline, usually prominently lobed on 

 either side about midlength, narrowing before 

 flaring to a broad, undulate-crenate and retuse 

 terminal lobe, the basal orifice leading into a 

 slightly curved spur 5-6 mm. (0.19-0.24 in.) long; 

 ovary green to purplish (adapted from Hitchcock et 

 al. , 1969) 



3. LOCAL FIELD CHARACTERS: Orchis rotundifolia is 



easily distinguished by its single roundish basal 

 leaf, its scapose flowering stem, and the distinct 

 magenta or purple spots on the flaring, lobed, lip 

 petal. Some species of the genus Habenaria rarely 

 have a single basal leaf, but the lip petal of 

 these plants is never spotted. 



GEOGRAPHICAL DISTRIBUTION 



1. RANGE: The known range of Orchis rotundifolia 



includes areas from Alaska to Greenland, south to 

 southern British Columbia, western Montana, north- 

 western Wyoming, Minnesota, Michigan, Wisconsin, 

 and New York. At the start of the 1988 field 

 season O. rotundifolia was known from only 4 

 locations in Montana. Extensive field surveys 

 conducted during the summer added a total of 13 

 new sites. Populations are known to occur in 

 Teton, Lewis and Clark, Pondera, and Powell 

 counties. A map of the distribution of the plant 

 populations within the state is included on p. 8. 



HABITAT 



ASSOCIATED VEGETATION: Orchis rotundifolia 

 generally occurs along streams and in bogs or wet 

 woods where drainage is good. It is often 

 associated with limestone substrates (Hitchcock et 

 al. , 1969). The population on the Ear Mountain 

 ONA occurs along the edges of a willow bog 

 composed primarily of Salix drummondiana . The 

 overstory is principally Picea engelmannii 

 (Engelmann spruce) . Associated plant species 

 include Dodecatheon pulchellum (few-flowered 

 shooting star) , Galium boreale (northern 

 bedstraw) , Fraqaria virginiana (Virgiriia 

 strawberry) , Aquilegia flavescens (yellow 

 columbine) , and Pyrola asarifolia (pink 

 wintergreen) . 



Most of the known sites that contain O. 

 rotundifolia also contain other plants rare in 



