MARCHANTIA

genus of liverworts (creeping ribbonlike plants) in the order Marchantiales, commonly found on moist clay or silty soils, especially on recently burned land throughout the Northern Hemisphere. Marchantia polymorpha, a well-known species, often is discussed as a representative liverwort in biology textbooks. Dark green Marchantia gametophytes (sexual plants) are branched and ribbonlike, about 1.3 cm (0.5 inch) wide and 5 to 13 cm long. The diamond-shaped markings on their upper surfaces, signs of interior air chambers, have a central pore through which air diffuses. Male and female plants have umbrella-like, stalked reproductive structures. The male structures are disk-shaped with scalloped edges; the female structures have nine fingerlike projections. Sperm produced by male plants are splashed by raindrops onto female plants. Sporophytes (asexual plants) develop from fertilized eggs in the female structures. Vegetative reproduction occurs in both male and female plants by means of rounded, fringed gemmae (asexual buds) or by pieces of the plant body that may break off and grow.