Abstract: The present paper involves descriptiins and discussions of some doubtful species in the genus Isachne. One species and two varieties are new, another species is newly reported from the main land of China, and the delimitation and rank of the other three species are reinvestigated and ascertained.

Key words: Isachne, I.guangxiensis, I.hirsuta var angusta, I.hirsute var.yongxiouensis, notes