The Collaborative International Dictionary of English v.0.48:

Agamous \Ag"a*mous\, a. [Gr. 'a`gamos unmarried; 'a priv. +
   ga`mos marriage.] (Biol.)
   Having no visible sexual organs; asexual. In (Bot.),
   cryptogamous.
   [1913 Webster]

WordNet (r) 3.0 (2006):

agamous
    adj 1: (of reproduction) not involving the fusion of male and
           female gametes in reproduction [syn: agamic, agamous,
           agamogenetic, apomictic, parthenogenetic]