lady's slipper, lady-slipper, ladies' slipper, slipper orchid(noun)

any of several chiefly American wildflowers having an inflated pouchlike lip; difficult or impossible to cultivate in the garden

Lady's slipper(u)

any orchidaceous plant of the genus Cypripedium, the labellum of which resembles a slipper. Less commonly, in the United States, the garden balsam (Impatiens Balsamina)