allogamy

from WordNet (r) 3.0 (2006)

allogamy
    n 1: cross-fertilization in plants [ant: {autogamy}]

from The Collaborative International Dictionary of English v.0.48

Allogamy \Al*log"a*my\n. [Gr. ? other + ? marriage.] (Bot.)
   Fertilization of the pistil of a plant by pollen from another
   of the same species; cross-fertilization.
   [1913 Webster]