In the alternation of generations in plants, that generation or phase which bears sex organs and produces gametes. In the lower plants, as the algæ, 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.  [Webster 1913 Suppl.]