Four species in the genus Zizania are known as wild rice, but they should not be confused with Asian rice (Oryza sativa), which is a plant in a different genus.
Three species originate from North America: Northern wild rice (Zizania palustris), Wild rice (Zizania aquatica), and Texas wild rice (Zizania texana). One species is native to Asia: Manchurian wild rice (Zizania latifolia).
Of all species the grains can be used as a cereal, but the Manchurian wild rice is nowadays mainly cultivated in China to use the thickened stems as a vegetable.
Manchurian wild rice
Northern wild rice
Texas wild rice