Liverworts(Marchantiophyta) may be viewed as the plants most closely related to the ancestor that moved to land. Liverworts have colonized many habitats on Earth and diversified to more than 6,000 existing species (Figure 14.10 a). Some gametophytes form lobate green structures, as seen in Figure 14.10b. The shape is similar to the lobes of the liver and, hence, provides the origin of the common name given to the division.
(a) A 1904 drawing of liverworts shows the variety of their forms. (b) A liverwort, Lunularia cruciata, displays its lobate, flat thallus. The organism in the photograph is in the gametophyte stage.