The Collaborative International Dictionary of English v.0.48:

Congener \Con"ge*ner\ (?; 277), n. [From L. congener. See
   Congenerous.]
   A thing of the same genus, species, or kind; a thing allied
   in nature, character, or action.
   [1913 Webster]

         The cherry tree has been often grafted on the laurel,
         to which it is a congener.               --P. Miller.
   [1913 Webster]

         Our elk is more polygamous in his habits than any other
         deer except his congener, the red deer of Europe.
                                                  --Caton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

congener
    n 1: a minor chemical constituent that gives a wine or liquor
         its distinctive character
    2: an animal or plant that bears a relationship to another (as
       related by common descent or by membership in the same genus)
       [syn: relative, congener, congenator, congeneric]
    3: a whole (a thing or person) of the same kind or category as
       another; "lard was also used, though its congener, butter,
       was more frequently employed"; "the American shopkeeper
       differs from his European congener"