Annual, biennial or perennial herbs, sometimes rhizomatous; plants bisexual or gynomonoecious. Leaves (at least at base) petiolate, lobed to ternately dissected, upper leaves less dissected; petioles sheathing at base. Inflorescence a simple, pedunculate umbel, terminal or leaf-opposed; involucral bracts narrow, simple, often united shortly at base. Sepals minute or absent; petals white, pink or blue. Fruit laterally compressed; mericarps c. semicircular, with a prominent to winged dorsal rib, often unequal in size, ornamentation, or sometimes 1 aborted; vittae lacking; carpophore simple, persistent.
About 55 species, from Australia, Melanesia, New Caledonia, Fiji; c. 46 species in Australia (38 endemic).