Petalophyllum
Petalophyllum, or petalwort, is a genus of liverworts in the order Fossombroniales. The plants are small, reaching lengths of up to about 15 mm (0.6 in), and thallose; that is, the plant is not differentiated into root, stem, and leaf. The thallus consists of a midrib flanked by two wings that bear leaf-like lamellae on their dorsal surface. The ventral surface bears rhizoids and two rows of small scales. "Petalophyllum" is dioicous. The gametangia are individually subtended by extensions of the dorsal lamellae. Antheridia occur in rows or clusters near the apex of the thallus. Archegonia are clustered  and surrounded by a pesudoperianth. Asexual reproduction occurs via apical tubers. Species. "Petalophyllum" lives primarily in seasonally dry habitats on disturbed soils and sand dunes in North America, western Europe, northern Africa, India, New Zealand, and Western Australia. There are currently five recognized species: