A new species and a new replacement name in Cynanchum (Apocynaceae: Asclepiadeae) from southwest China

Cynanchum pingtaoi sp. nov. (Apocynaceae), from Yunnan Province, China, is described and illustrated based on molecular and morphological evidence. Its deeply cordate to reniform leaves, campanulate and large flowers show that it is a member of former Raphistemma which has been included in Cynanchum now. It is different from the all former Raphistemma species (C. hooperianum,C. longhushanense and C. pulchellum) by the broadly ovate corolla lobe, purple-red corolla, and connivent corona tip slightly exceeding corolla throat. Its detailed morphological description and illustrations are provided. Meanwhile, Cynanchum longhushanense (Y. Wan) G.D.Tang & Miao Liao nom. nov. is proposed as the replacement name of Raphistemma brevipedunculatum Y. Wan which is reinstated from a synonym of C. hooperianum (Blume) Decne because of their significant morphological differences.