A phylum embracing the highest plants, or those that produce seeds; the seed plants, or flowering plants. They form the most numerous group, including over 120,000 species. In general, the group is characterized by the marked development of the sporophyte, with great differentiation of its parts (root, stem, leaves, flowers, etc.); by the extreme reduction of the gametophyte; and by the development of seeds. All the Spermatophyta are heterosporous; fertilization of the egg cell is either through a pollen tube emitted by the microspore or (in a few gymnosperms) by spermatozoids.

n. (Gr. sperma, seed; phyton, plant) a major division of the plant kingdom, characterized by reproducing by seed and subdivided into the Gymnospermae and Angiospermae.

seed plants; comprises the Angiospermae (or Magnoliophyta) and Gymnospermae (or Gymnospermophyta); in some classification systems Spermatophyta is coordinate with Pteridophyta (spore producing plants having vascular tissue and roots) and Bryophyta (spore producing plants lacking vascular tissue and roots)