Description from Flora of China
Monoecious aquatic annuals or perennials, rhizomes and stolons sometimes present. Culms tall, erect, robust. Leaf blades linear to broadly lanceolate; ligule membranous. Inflorescence a large panicle, spikelets unisexual and mostly borne on separate branches; lower branches spreading, bearing pendulous, caducous male spikelets; upper branches erect or ascending at maturity, bearing appressed, tardily deciduous female spikelets; or middle branches with mixed male and female spikelets (Z. latifolia). Spikelets with 1 floret, falling entire; glumes absent; lemma as long as spikelet, 5-veined; palea subequal to lemma, narrower, 3-veined. Male spikelet: lemma membranous, weakly flattened, acuminate or awn-pointed; stamens 6. Female spikelet: lemma papery or leathery, cylindrical, tapering into a long slender awn; palea closely clasped by lemma. Caryopsis cylindrical, embryo half as long, hilum almost as long as caryopsis. x = 15 or 17.
All species are used as food crops. Zizania aquatica Linnaeus and Z. palustris Linnaeus are cultivated in botanical gardens in China. They are highly valued cereals in North America (Wild Rice).
Four species: E Asia and North America; one species in China.