5. Hydrocharis L., Sp. Pl. 1036. 1753. Gen. Pl. ed. 5.458. 1754; Benth. & Hook. f., Gen. Pl. 3:452. 1883; Hook. f., Fl. Brit. Ind. 5:662. 1888; Hartog in van Steenis, Fl. Males. 1(5):394. 1957; Cook & Aquat. Bot. 14:177-204. 1982.
Monoecious, free floating or rooting in shallow water, perennial herbs, with short stoloniferous stems. Leaves petiolate, in a basal rosette, ovate-suborbicular, cordate-reniform at the base, apically obtuse or subacute, entire; stipules 1 or 2, transparent, scarious. Flowers unisexual, actinomorphic, males 1.4, females solitary. Male spathe pedunculate, with lanceolate membranous segments. Male flowers: shortly pedicellate; sepals 3, oblong-elliptic, obtuse, white or greenish-white, persistent; petals 3, broad obovate, white, apex rounded, much broader and longer than the sepals, membranous; stamens 9-12, anthers dorsifixed, dithecous; pistillode present, spathe sessile otherwise similar to male. Female flowers: long pedicelled, protruding out of the spathe; sepals and petals as in the male; ovary elliptic; styles 6, free, flat, shortly 2-lobed. Fruit elliptic to globose, 6-ribbed, falsely 6-chambered, many-seeded, pulpy and berry-like, rupturing irregularly at the apex. Seeds ellipsoid with pulpy testa.
A genus of 3 species, distributed in Europe, tropical Africa, Asia and temperate Australasia. Represented here by the following species.