Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
higher (vascular) plants that form seeds. The plants comprise the Gymnospermae (including many fossil groups, such as Lyginopteridopsida, Bennettitales, and Cordai-tales) and Angiospermae. Other higher plants, for example, Rhyniophyta, Bryophyta, Lycopodiales, Psilophyta, Equiseta-ceae, and Polypodiophyta, do not form seeds.
In Spermatophyta the gametophyte, that is, the sexual generation, is reduced, especially in angiosperms, and develops on the sporophyte. Reproduction by seeds is progressive adaptation in comparison with reproduction only by spores. Spermatophyta evolved from spore plants; this is indicated by homology between organs of reproduction in Spermatophyta and vascular spore plants. Spermatophyta play an especially important role in the world’s plant cover and in man’s economic activity. Earlier, when the sexual process had not yet been sufficiently studied, Spermatophyta were called Phanerogamae, in contrast to spore plants, which were known as Cryptogamae.
REFERENCESTakhtadzhian, A. L. Vysshie rasteniia, vol. 1. Moscow-Leningrad, 1956.
Osnovy paleontologii: Golosemennye i pokrytosemennye. Moscow, 1963.
Lehrbuch der Botanik für Hochschulen, 30th ed. Jena, 1971.
M. E. KIRPICHNIKOV