Bryophytes
Bryophytes, collective term applied to about 22,000 species of small plants that usually grow in moist areas on soil, tree trunks, and rocks. Bryophytes are nonvascular embryo-bearing plants of three plant divisions: the Bryophyta ( mosses ), the Hepatophyta ( liverwort ), and the Anthocerophyta (hornworts). Historically, these phyla were considered to be a monophyletic group and were thus placed as classes within an inclusive Bryophyta. In their level of organization, the bryophytes lie between the green algae, Chlorophyta, from which they most likely have evolved, and the simpler lower vascular plants such as the Lycopodiophyta (see Lycopsid ). Bryophytes are similar to higher plants in that the fertilized egg develops into an embryo, a cell mass dependent on the gametophyte (the sexual plant). Bryophyte embryos, however, develop into sporophytes (asexual plants), which, unlike those of higher plants, remain almost entirely dependent on the gametophytes and have no leaves, stems, or