Great Plains Ladies’-tresses, Spiranthes magnicamporum: disjunct in eastern Ontario and a new orchid species for the Ottawa District and Lanark County

Joyce M. Reddoch, Paul M. Catling, Allan H. Reddoch


We report the discovery of Great Plains Ladies’-tresses, Spiranthes magnicamporum (Orchidaceae), in eastern Ontario, 250 km east of its previously known eastern occurrence in Ontario. The population of more than 500 flowering plants (in 2013) was confined to Prairie Dropseed, Sporobolus heterolepis, grasslands within the Burnt Lands Alvar. Peak flowering was in late September, two weeks later than that of Nodding Ladies’-tresses, Spiranthes cernua, in the same area.


Great Plains Ladies’-tresses; Spiranthes magnicamporum; Ottawa District; Lanark County; eastern Ontario; Burnt Lands Alvar; alvar; disjunct population; range extension

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