liverwort

Liverworts are non-vascular land plants in the division Marchantiophyta. They are among the simplest and oldest lineages of terrestrial plants, occurring in a wide range of moist habitats worldwide, including soil, rocks, tree bark, and stream banks. They come in two main body forms: thallose liverworts, which have a flattened, leafless body, and leafy liverworts, whose dorsal surfaces bear leaf-like structures arranged in two visible ranks. They lack true roots, instead anchoring with rhizoids, and most have a waxy cuticle that helps retain moisture.

Liverworts rely on diffusion for water and nutrient transport because they do not possess true vascular tissue. Gas exchange and photosynthesis occur across their surface; in many species the sporophyte develops within or atop the gametophyte and remains dependent on it for sustenance. Reproduction occurs sexually or asexually. Sexually, liverworts produce antheridia (male) and archegonia (female) on separate or mixed plants, requiring a films of water for sperm to swim to the egg. The resulting sporophyte releases spores, often aided by elaters in many thallose and leafy species. Asexually, they propagate via fragmentation or gemmae cups in leafy species, which produce miniature sporophyte-like propagules that disperse when rains splash them away.

Habitat preferences emphasize moist and shaded environments, though some species tolerate a wider range of conditions, including cold or aquatic niches. Ecologically, liverworts contribute to soil formation and moisture regulation, participate in nutrient cycling, and serve as indicators of environmental conditions. In scientific research, their simple body plan provides insight into early land plant evolution and the transition from aquatic to terrestrial life.