Chassalia petitiana (Rubiaceae-Psychotrieae), an overlooked epiphytic species hidden in the African canopy

Morphological (including pollen morphology) and wood anatomical characters of the poorly known species 'Psychotria epiphytica' from tropical Africa ar e documented and described. It is the only record of genuine epiphytism for African Rubiaceae. The species is characterized by its inaperturate pollen grains with peculiar reticulate exine structure, and pyrenes that lack a c lear ventral excavation and open with one mediodorsal and two lateral prefo rmed germination slits; another remarkable feature is the unusual variation in stipule morphology. It is proposed to transfer the species to Chassalia . A new name, Chassalia petitiana, is given because of the illegitimate sta tus of the original name. Psychotria euchlora, a probably closely related s pecies from Sao Tome, is also discussed.