Source : Webster's Revised Unabridged Dictionary (1913)

Gametophyte \Ga*me"to*phyte\, n. [Gamete + Gr. fyto`n plant.]
   (Bot.)
   In the alternation of generations in plants, that generation
   or phase which bears sex organs. In the lower plants, as the
   alg[ae], the gametophyte is the conspicuous part of the plant
   body; in mosses it is the so-called moss plant; in ferns it
   is reduced to a small, early perishing body; and in seed
   plants it is usually microscopic or rudimentary.

Source : WordNet®

gametophyte
     n : the gamete-producing individual or phase in the life cycle
         of a plant having alternation of generations