Marchantiophyta

Marchantiophyta, commonly known as liverworts, is a division of non-vascular land plants. They are among the earliest diverging lineages of terrestrial plants and, with mosses and hornworts, form the bryophytes. Liverworts are small and inconspicuous, inhabiting moist, shaded environments worldwide. About 9,000 species exist, and the life cycle is dominated by the haploid gametophyte.

Body forms fall into two groups: thalloid liverworts with flattened thalli, and leafy liverworts with leaf-like organs in two ranks. Both lack true roots and use rhizoids for anchorage. The thallus often contains air pores for gas exchange.

Reproduction: Liverworts produce archegonia and antheridia. Fertilization requires liquid water for motile sperm. The sporophyte is dependent on the gametophyte and releases spores from a capsule, aided by elaters in many species; the calyptra covers the capsule early. Asexual reproduction occurs via gemmae cups and fragmentation.

Ecology and distribution: They occupy soils, decaying wood, rocks, and tree trunks in forests, wetlands, and humid regions. Liverworts contribute to soil formation and nutrient cycling and serve as microhabitats for invertebrates. They are sensitive indicators of humidity and air quality, and habitat loss threatens many species.

Taxonomy and classification: Marchantiophyta is one of three divisions traditionally called bryophytes, alongside Bryophyta and Anthocerotophyta. Modern classifications divide liverworts into lineages such as Marchantiopsida (thalloid) and Jungermanniopsida (leafy). Molecular data continue to refine their relationships.