Decanema

Decanema is a small genus in the dogbane family first described as a genus in 1838. The group is endemic to Madagascar.
;Species

Decanema bojerianum Decne. - Madagascar
Decanema luteifluens Jum. & H.Perrier - Madagascar

;formerly included

Decanema grandiflorum Jum. & H.Perrier, synonym of Cynanchum grandidieri Liede & Meve.