Morphologically, C. brevicaudata, C. pinnata, and C. heracleifolia are strikingly different and easy to distinguish. Clematis brevicaudata is a climbing species with bi-ternate leaves, white flowers, spreading sepals and glabrous anthers. Whereas C. heracleifolia is an erect sub-shrub with ternate leaves, blue flowers. with erect sepals and hairy anthers. Finally, C. pinnata specimens are often creeping herbs with pinnate leaves, bluish-white flowers, erect or spreading sepals and anthers with hairs that are not easily perceived (Xie et al. 2005). Clematis brevicaudata and C. heracleifolia belong to different sections in all current taxonomic treatments because of differing floral structure (Table 1), whereas the position of C. pinnata was ambiguous based on morphology (see Xie et al. 2005). In a recent revision, Wang & Xie (2007) placed C. pinnata in sect. Tubulosae. Although C. brevicaudata was considered quite different