The Collaborative International Dictionary of English v.0.48:

Callistephus \Callistephus\ n.
   a genus of plants having only one species, an erect Asiatic
   herb with large flowers.

   Syn: genus Callistephus.
        [WordNet 1.5] Callisthenic

WordNet (r) 3.0 (2006):

Callistephus
    n 1: one species: erect Asiatic herb with large flowers [syn:
         Callistephus, genus Callistephus]