Subtribal division of Ceropegieae (Apocynaceae-Asclepiadoideae)

Monophyly and sister group relationship of Ceropegieae and Marsdenieae, the two Asclepiadoideae tribes possessing erect pollinia, are confirmed by molecular investigation of non-coding cpDNA markers (trnT-L and trnL-F spacers, and the trnL intron). In Ceropegieae, the analyzed taxa fall in four subclades. The Heterostemma subclade is sister to other three subclades, of which the Conomitra-Leptadenia-Orthanthera subclade is sister to the Anisotoma-Neoschumannia-Riocreuxia-Sisyranthus subclade and to the large subclade comprising the stem-succulent stapeliads, Brachystelma and Ceropegia. Following these results, subdivision of Ceropegieae into four subtribes, Anisotominae, Heterostemminae, Leptadeniinae and Stapeliinae, is proposed.