Cypripedium acuale (Pink Lady's Slipper Orchid) closeup of flower showing pollinium.
Cypripedium acuale (Pink Lady's Slipper Orchid) closeup of flower showing pollinium (waxy mass of pollen grains) which is the yellow-green disc-shaped object in the flower. About 30 of these plants were found growing in a northern Minnesota conifer swamp composed of Black Spruce (Picea mariana) and Tamarack (Larix laricina) growing in a thick bed of Sphagnum moss. I have occasionally found this species in dry Jack Pine (Pinus banksiana) forests if there is a thick bed of moss such as Pleurozium schreberi.
''Cypripedium acaule'' is a member of the orchid genus ''Cypripedium''. Members of this genus are commonly referred to as lady's slipper orchids. First described in 1789 by Scottish botanist William Aiton, ''C. acaule'' is commonly referred to as the pink lady's slipper, stemless lady's-slipper, or moccasin flower. The pink lady's slipper is the provincial flower of Prince Edward Island, Canada and the state wildflower of New Hampshire, United States.