Lady's Slipper (Cypripedium Calceolus), formerly known as Calceolus marianus, one of the rarest of British orchids. The genus includes some fifty species from various tropical and temperate regions. The large inflated lip-petal gives its name to the group, and it differs from other orchids in having the outer anterior stamen aborted and two inner lateral ones polliniferous. There is also a pedicellate 3-lobed discoid stigma. Many of the species are favourite stove-plants.