对作透骨草入药的５种铁线莲属植物：黄花铁线莲Ｃｌｅｍａｔｉｓｉｎｔｒｉｃａｔａ、芹叶铁线莲Ｃ．ａｅｔｈｕｓｉｆｏｌｉａ、粉绿铁线莲Ｃ．ｇｌａｕｃａ、甘青铁线莲Ｃ．ｔａｎｇｕｔｉｃａ和棉团铁线莲Ｃ．ｈｅｘａｐｅｔａｌａ的茎进行了比较形态组织学研究，发现了茎中由初生韧皮纤维束和木化孔纹细胞组成的厚壁细胞环带及薄壁性三生构造环带，并提出了形成层环直径比的参数用于鉴别。根据厚壁细胞环带的有无、毛茸的大小和细胞个数，纤维细胞壁的厚度及ＲＣＲ值等列出了比较表和检索表，利用检索表可准确鉴别这５种植物 Five species of clematis used as medicine: S. clematis Clematisintricata, C. communis Clematis Aethusifolia, Pink Green Clematis C. Glauca, ganqing clematis C. Tangutica and cotton ball clematis C. The morphological and histological studies of the hexapetala stems revealed that thick-walled cell bands and thin-walled three-biotectonic rings composed of primary bast fiber bundles and lichangular cells were found in stems, and a layered ring was proposed. The diameter ratio parameter is used for identification. Based on the presence or absence of thick-walled cell annulus, the size of hairs, the number of cells, the thickness of the cell wall, and the RCR values, a comparison table and a search table are listed. The use of a search table can accurately identify these five plants.