A plant that produces seeds. The gymnosperms and the angiosperms together form the seed-bearing plants. The seed-bearing plants have been an enormously successful group in the history of life, owing to the evolution of seeds and pollen. The seed is a superior unit of dispersal to the naked spore, since it includes a food reserve and, among angiosperms, a protective layer. Also, seedless plants are dependent upon the presence of liquid water for sperm dispersal. Pollen makes water unnecessary for sperm transport. Instead, eggs are fertilized after male nuclei have been transported within the protective pollen grain to the female reproductive parts, usually by pollinating agents such as insects or the wind. Also called seed plant, spermatophyte.