The Collaborative International Dictionary of English v.0.48:

Callirhoe \Callirhoe\ n.
   small genus of North American herbs having usually red or
   purple flowers.

   Syn: genus Callirhoe.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Callirhoe
    n 1: small genus of North American herbs having usually red or
         purple flowers [syn: Callirhoe, genus Callirhoe]