Vincetoxicumnakaianum (Asclepiadoideae, Apocynaceae), a new species from Japan for Cynanchummagnificum Nakai, nomen nudum.

Vincetoxicum Wolf is the third largest genus in Asclepiadoideae, and 23 species are distributed in Japan. We discovered that an erect herb species, distributed in the eastern part of the Honshu island, was invalidly named Vincetoxicummagnificum (Nakai) Kitag. based on Cynanchummagnificum Nakai, nomen nudum. Therefore, we presently name this species Vincetoxicumnakaianum K.Mochizuki & Ohi-Toma, and we give a detailed description in this study. Additionally, we provide photographs that demonstrate its ecology and diagnostic characteristics.
Competing Interests: The authors have declared that no competing interests exist.
(Ko Mochizuki, Shuichi Nemoto, Jin Murata, Tetsuo Ohi-Toma.)