The Collaborative International Dictionary of English v.0.48:

Colocasia \Colocasia\ n.
   a small genus of perennial tuberous herbs of the arum family,
   of tropical Asia and the Pacific islands, including the
   taro (Colocasia esculente).

   Syn: genus Colocasia.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Colocasia
    n 1: small genus of perennial tuberous herbs of tropical Asia:
         taro [syn: Colocasia, genus Colocasia]