bryophytes

Bryophytes are a diverse group of non-vascular land plants that includes liverworts (Marchantiophyta), mosses (Bryophyta), and hornworts (Anthocerotophyta). They are characterized by the absence of true vascular tissue (xylem and phloem) and by a life cycle dominated by a haploid gametophyte generation. They possess simple bodies: leafy stems in many mosses, thalloid or leafy forms in liverworts, and horn-like sporophytes in hornworts. They lack true roots, instead using rhizoids for anchorage and mineral uptake.

Life cycle: Bryophytes exhibit alternation of generations, with the gametophyte producing sex organs that generate eggs and sperm. Fertilization requires free water, and the resulting diploid sporophyte is usually dependent on the gametophyte for nutrition. The sporophyte bears a sporangium that releases spores; in mosses the sporophyte typically consists of a stalk (seta) and a capsule, while in liverworts the sporophyte is often shorter and in hornworts the sporophyte is horn-shaped and frequently photosynthetic.

Ecology: They inhabit moist, shaded environments but can tolerate dryness by entering dormancy. Bryophytes contribute to soil formation, peat formation (notably Sphagnum mosses), and water retention in ecosystems. They are often epiphytic on rocks, soil, or tree bark and can act as pioneers in bare substrates, helping to stabilize surfaces and create microhabitats.

Evolution and classification: Bryophytes are among the earliest diverging lineages of land plants, and molecular data place them as a paraphyletic group outside the vascular plants. They serve as model systems for studying plant evolution, reproduction, and stress responses.

Conservation and human use: Many species are sensitive to air and water pollution and habitat destruction. Bryophytes are used as bioindicators and in horticulture or traditional medicine in some regions; their presence also informs ecological assessments and peatland conservation.