Marchantia

Marchantia polymorpha, the common or umbrella liverwort, is a large thalloid liverwort in the class Marchantiopsida, highly variable in appearance and divided into several subspecies. It grows as a rosette of flattened, forked thalli, typically about 10 centimeters long and 2 centimeters wide, green when young and turning brown or purplish with age, anchored to the ground by root-like rhizoids. Dioicous, with separate male and female individuals, it reproduces sexually through umbrella-shaped structures bearing sperm and eggs and asexually through gemmae released from small cups on the thallus and scattered by raindrops. Marchantia polymorpha grows in shaded, moist soil and rock in damp places such as streambanks, bogs, fens and dune slacks, and occurs worldwide except Antarctica; scientists study it for how it recolonizes burned ground and as a bioindicator of heavy-metal pollution.