Abstract: This Paper deals with gross morphology of Zizania L. and its relatives. A total of 8 genera, 12 species, 3 varieties and 1 form were examined not only in some collections of herbarium but also in the field of Nanjing Botanical Garden Mem. Sun Yat-sen. The results, just as other characters, were suggested that genus Zizania may be considered as an isolated subt-ribe Zizaniinae in tribe Oryzeae. There are 4 species, 2 subspecies in the whole world, i. e. Z. aquatica subsp. aqualica, Z. aqualica subsp. brevis(Fassett) S. L. Chen, Z. palustris subsp. palustris, Z. palustris subsp. interior (Fassett) S. L. Chen. Z. texana Hitchc. and Z. latifolia (Griseb.)Turcz. ex Stapf. The evolutionary trend of this genus, Zizania, may bederived from ancient stock, Which also given rise to the genus either Oryza or Zizaniopsis, and therefore parallel evolution may have takenplace in tribe Oryzeae.