Description from Flora of China
Herbs, perennial or annual, in fresh to brackish water, totally submerged or with floating leaves. Rhizomes present or absent. Stems elongated or shortened, terete to compressed, rarely strongly compressed. Leaves alternate or basal, occasionally opposite or subopposite; stipules free from leaves or adnate to leaf base and sheathing stems. Inflorescence a capitate spike, terminal or axillary. Plants monoecious; flowers small, bisexual. Perianth bractlike, free, present or absent. Stamens (1-)4; anthers sessile, (1 or)2-celled, extrorse, longitudinally dehiscent. Carpels (1-)4, free; ovule solitary. Fruit drupaceous. Embryo curved; endosperm absent.
Guo Youhao & Li Qingyi. 1992. Potamogetonaceae (excluding Halodule, Phyllospadix, Posidonia, Ruppia, Syringodium, Triglochin, and Zostera). In: Sun Xiangzhong, ed., Fl. Reipubl. Popularis Sin. 8: 40-83.
Three genera and ca. 85 species: cosmopolitan; two genera and 24 species in China.
(Authors: Guo Youhao (郭友好); Robert R. Haynes, C. Barre Hellquist, Zdenek Kaplan)