Taylor, C.M., S.G. Razafimandimbison, L. Barrabé, J.G. Jardim & M.R.V. Barbosa (2017). Eumachia expanded, a pantropical genus distinct from Psychotria (Rubiaceae, Palicoureeae). Candollea 72 : 289–318. In English, English abstract.

The pantropical genus Margaritopsis C. Wright (Rubiaceae, Palicoureeae) was recently separated from Psychotria L. and transferred to a different tribe, Palicoureeae, based on both molecular and morphological data. Margaritopsis has been studied in the Neotropics, and in Africa as Chazaliella E.M.A. Petit & Verdc.; the species that belong to this group in the Pacific are enumerated for the first time here. Recently Eumachia DC. was found to be an older name for this group, and a few species of Margaritopsis have been transferred nomenclaturally to that genus. Here Eumachia is surveyed comprehensively for the first time, with a list of species and an overview of morphological characteristics. The remaining species of Margaritopsis are nomenclaturally transferred here to Eumachia, along with one species of Hodgkinsonia F. Müll., one species of Mapouria Aubl., and several species of Psychotria from Asia, Australia, New Guinea, and the Pacific region. In this new circumscription Eumachia includes 83 species, and is characterized within Palicoureeae by a yellowish green drying color; stipules that are persistent or fall by fragmentation and are generally glandular when young and hardened when old; green to whitened inflorescence axes; white to cream or yellowish green, often rather small corollas; orange to red fruits; pyrenes with marginal pre-formed germination slits and no ethanol-soluble pigments; and non-ruminate endosperm. Eumachia includes 20 species, 8 subspecies, and 7 varieties in Africa, 27 species in the Neotropics, and 36 species and 6 varieties in Asia, Australasia, and the Pacific region. Here we publish 81 new nomenclatural combinations in Eumachia and two new synonymies for Neotropical names, and 11 names from various regions are lectotypified.

Received: March 15, 2017; Accepted: June 14, 2017; First published online: July 20, 2017