Merriam-Webster Collegiate Dictionary - gametophyte

 noun  Etymology: International Scientific Vocabulary  Date: circa 1889 the haploid generation of a plant or fungus with alternation of generations that begins with haploid spore- or gamete-producing bodies and ends with fertilization producing a diploid zygote and that constitutes the visibly dominant form in mosses, algae, and fungi, exists as an independent plant body in ferns and their relatives, and is reduced to a microscopic or rudimentary state in seed plants; also an individual of this generation — compare sporophyte  • gametophytic adjective