The Collaborative International Dictionary of English v.0.48:

fairy-slipper \fairy-slipper\ n.
   a rare north temperate bog orchid (Calypso bulbosa) bearing
   a solitary white to pink flower marked with purple at the tip
   of an erect reddish stalk above one basal leaf.

   Syn: calypso, Calypso bulbosa.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Calypso bulbosa
    n 1: rare north temperate bog orchid bearing a solitary white to
         pink flower marked with purple at the tip of an erect
         reddish stalk above 1 basal leaf [syn: calypso, fairy-
         slipper, Calypso bulbosa]