"Oryza longistaminata is a perennial species of grass from the same genus as cultivated rice (O. sativa). It is native to most of sub-Saharan Africa and Madagascar. It has been introduced into the United States, where it is often regarded as a (noxious) weed. Its common names are longstamen rice and red rice.The host resistance gene, Xa21, from O. longistaminata, has been integrated into the genome of O."@en . . . . . . . . .