Lady's Slipper, common name for some members of the orchid family in which modified petals (labella) fold inward to make the toe of the "slipper." Insects must pass through the structure to obtain nectar, pollinating the plant in the process. Only the genus Cypripedium is hardy enough to withstand the Canadian climate. Its 50 species are scattered throughout northern temperate regions of America and Eurasia. Of the 13 N American species, 8 are native to Canada. The pink or stemless lady's slipper (C. acaule), also known as moccasin flower, has 2 leaves at the base of the plant and produces a single flower. The 5 cm long slipper is split along its length.

This spring-flowering plant grows in moist places, preferably in acidic soil, from Newfoundland to Manitoba. The lady's slipper was selected (1947) as the Provincial Floral Emblem of PEI. The showy lady's slipper (C. reginae) was chosen first but, because it is rare, was replaced in 1965 by the pink lady's slipper. As it is difficult to grow, the lady's slipper should not be disturbed in its native stands. The sedative qualities of a root infusion of yellow lady's slipper (C. calceolus) or of moccasin flower were known to Canadian native people.

See also Aboriginal Uses of Plants.