Abstract: Clematis is one of the largest genera in Ranunculaceae with important horticultural value.In recent years,large amount of molecular phylogenetic as well as phylogenomic studies had been published.The results greatly changed the delimitation of the genus Clematis.Previously recognized genera,such as Archiclematis and Naravelia within subtribe Clematidinae,should be merged into Clematis based on phylogenetic analysis.As a result,Clematis should be defined in broad sense with more species than previous delimitation.Based on a comprehensive review of previous taxonomic and molecular systematic studies,major groups of Clematis s.l.,wild species resources,and their horticultural importance in China were summarized.