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 (seealternation 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.