Abstract: The distinct characters of the flower of Plagiostachys elliptica, S. Q. Tong et Y. M. Xia are: (1) each flower possesses two large lateral staminodes, which are adnate to the lip (labellum) to form a deeply 3 lobed labellum;(2) connective extends into a curved, beaklike conspicuous appendage (anther crest) and envelops the upper part of style. In the Zingiberaceae, these characters are only present in the genus Zingiber.Furthermore, in Sect. Pleuranthesis of Zingiber the spike also arises from side of the leafy stem. Pollen grains of the species are with cerebelloid sculpture,that is the character of the Subtype Cerebelloid areolate in Zingiberaceae, and are similar to those sculpture and morphology of Sect. Zingiber of the genus Zingiber and differ from those of Plagiostachys, of which pollen grains are with longer spines and belong to the Group longspinate of Subtype spinate. The endotesta of seeds in this species is composed of one layer of brick shaped parenchymatous cells, which is similar to the parenchymatous endotesta of Zingiber seeds and obviously differs from that of seeds of Plagiostachys, which consists of one layer of sclereids. Therefore,Plagiostachys elliptica S. Q. Tong et Y. M. Xia should be transferred from Plagiostachys to the genus Zingiber, and a new combination——Zingiber ellipticum (S. Q. Tong et Y. M. Xia) Q. G. Wu et T. L. Wu is made in this paper.

Key words: Zingiber, Z. ellipticum, Plagiost achys, P. elliptica, Systematic position