Thalloid Liverworts

This group gathers Mosses and Liverworts subcategory members belonging to the thalloid, or thallose, liverworts, a growth form found chiefly within the class Marchantiopsida in which the plant body forms a flat, ribbon-like or lobed structure called a thallus, entirely lacking the stems and separate leaves that both true mosses and the leafy liverworts gathered separately possess. It spans the genus Riccia, whose species include both fully terrestrial forms that grow pressed flat against damp soil and the floating crystalwort, an aquatic species popular among freshwater aquarium hobbyists, the great scented liverwort of the genus Conocephalum, notable for a strong, distinctive scent when its thallus is crushed or damaged, and the crescent-cup liverwort of the genus Lunularia, named for the small, crescent-shaped cups on its thallus surface that hold asexual reproductive structures called gemmae. Nearly every thalloid liverwort gathered here reproduces both sexually, through spores, and asexually, through gemmae or simple fragmentation of the thallus itself, giving the group two largely independent routes to spreading into new ground.