Wild rice does not absolutely refer to the wild species of Oryza

Wild species of rice in Oryza genus,was usually translated into wild rice in English,but we found wild rice refered to not only the wild species of rice in Oryza genus,but also the genus Zizania in some literatures in English.Therefore,this article would discuss in two parts,the comparison between wild rice(Oryza) and Zizania,wild rice being not absolutely refering to the wild species of Oryza.This article would provide helpful guiding for people to understand the real meaning of wild rice which occured in English literature.