The Collaborative International Dictionary of English v.0.48:

Strophanthus \Stro*phan"thus\, n. [NL., from Gr. ? a turning + ?
   a flower.] (Bot.)
   A genus of tropical apocynaceous shrubs having singularly
   twisted flowers. One species (Strophanthus hispidus) is
   used medicinally as a cardiac sedative and stimulant.
   [1913 Webster]

WordNet (r) 3.0 (2006):

strophanthus
    n 1: any of various shrubs or small trees of the genus
         Strophanthus having whorled leaves and showy flowers of
         various colors in dense and corymbose clusters; some have
         poisonous seeds