Memoires de la Classe des Sciences Mathematiques et Physiques de L'Institut National de France 12(2): 9, 61, 73, plate 2a–k. 1814
Plants perennial, of fresh or brackish waters. Rhizomes present, stolons absent. Erect stems rooted in substrate, branched or unbranched, elongate. Leaves cauline, whorled, 3–8 per node, submersed, sessile; blade linear, rarely slightly elliptic, base tapering to stem, apex acute; midvein without lacunae along side(s), blade uniform in color throughout; abaxial surface ly with prickles along midvein, without aerenchyma; intravaginal squamules fringed with orange-brown hairs. Inflorescences 1-flowered, sessile to subsessile; spathe not winged. Flowers unisexual, staminate and pistillate on different plants or on same plants, submersed, sessile; petals whitish to reddish. Staminate flowers: filaments distinct, released under water, rising to surface; anthers oval; pollen in monads; . pPistillate flowers: ovary 1-locular; floral tube long, styles 1, not 2-fid. Fruits linear, cylindric, smooth or with simple spiny processes, indehiscent. Seeds cylindric, glabrous.
Introduced; North America, Central America, South America, Eurasia, Africa, Australia.
Allen, G. E. 1976. Investigations and current status of insect enemies as biological control agents of aquatic weeds. In: C. K. Varshney and J. Rzóska, eds. 1976. Aquatic Weeds in South East Asia. The Hague.