Spiranthes magnicamporum (Great Plains Ladies'-tresses)
|Also known as:||Late-flowering Ladies-tresses|
|Habitat:||part shade, sun; moist open prairie|
|Bloom season:||August - September|
|Plant height:||4 to 16 inches|
|Wetland Indicator Status:||GP: FAC MW: FAC NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Flowers are closely intertwined in 3 rows, spiraling up a 1 to 4 inch spike with up to 48 blossoms, typically 3 to 4 flowers in 1 cycle of the spiral. The petals and sepals are white except for a tinge of yellow on the lower lip, up to ½ inch long, opening out creating a winged trumpet like appearance. The end of the lower lip unfurls down like a ruffled tongue while the 2 narrow lateral sepals flare out and up. often above the flower. The side and upper petals overlap creating a narrow lance-like hood curled up at the tips. The green bracts are oval, curling around the ovary before tapering to a sharp tip above the flower.
Leaves and stems:
Basal leaves are long and slender, up to 5½ inches long, ½ inch wide and wilt away around 2 weeks before the flowers appear. The stem is stiffly erect with 4 to 6 sheath-like bracts that wrap the stem, the tips over lapping the base of the bract above.
Until 1973, Great Plains Ladies'-tresses was considered to be the same species as Nodding Ladies'-tresses (Spiranthes cernua). Habitat is one distinguishing characteristc, S. magnicamporum preferring open prairie and higher pH soils and is found in both low, moist areas and higher, gravelly sites. In appearance the differences are more subtle; unlike S. cernua, the lateral sepals are more flaring, often above the flower. The marked absence of lower leaves at flowering time is also key to an ID.
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Photos by K. Chayka taken at Whitewater WMA, Winona County, and in McLeod County. Photos courtesy Peter M. Dziuk taken in Douglas, McLeod and Winona counties.
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