Abstract: Trichosanthes is one of the larger genu in Cucurbitaceae, and most of them have medicinal values. In this paper, phylogenetic relationships of 16 species were inferred using nrDNA ITS sequences. The main implications of the phylogenetic trees analyses include: There was an evidence regarding sect. Truncata, which had traditional classification dispute, was not recognized as separate entity, but nested within sect. Involucraria, formed a subsect group. According to phylogenetic analyses the level of nucleotides of ITS sequence, and combining with morphological characteristics of T.guizhouensis, we suggested it should be incorporated into T.rosthorni. sect. Trichosanthes. belong to an independent species but also be in sect. Foliobracteola. In addition, T.dafangensis, an endemic species of Guizhou province, our result showed that it was a sister clade in sect. Trichosanthes, and was in a transition position to sect. Foliobracteola group, combining with its morphology analyses, it should be as a member of sect Trichosanthes.

Key words: nrDNA ITS, Trichosanthes, phylogentic