liverwort, any plant of the class Marchantiopsida. Mosses and liverworts together comprise the division Bryophyta, primitive green land plants (see moss; plant); some of the earliest land plants resembled modern liverworts. In contrast to mosses, most liverworts grow prostrate and consist of a flattened, branching (but undifferentiated) green structure, the thallus; other liverworts produce leafy stems, which are flattened and usually prostrate. The ancients believed that liverworts could cure diseases of the liver, hence the name. They are also called hepatics, and the unrelated flowering plant hepatica is frequently called liverwort. Liverworts are classified in the division Bryophyta, class Marchantiopsida.

Any of more than 8,000 species of small, nonvascular, spore-producing land plants that make up the class Hepatopsida (or Hepaticae) of bryophytes, found worldwide but mostly in the tropics. Thallose liverworts commonly grow on moist soil or damp rocks; leafy liverworts are found in similar habitats and on tree trunks in damp woods. Sexual (gametophyte) and asexual (sporophyte) generations alternate in the life cycle (see alternation of generations). The thallus of thallose liverworts, resembling a lobed liver, gives liverworts their name. Though not economically important to humans, liverworts provide food for animals, facilitate the decay of logs, and aid in the disintegration of rocks by their ability to retain moisture.

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