Eumachia expanded, a pantropical genus distinct from Psychotria (Rubiaceae, Palicoureeae) Charlotte M. Taylor, Sylvain G. Razafimandimbison, Laure Barrabé, Jomar G. Jardim & Maria Regina V. Barbosa Abstract TAYLOR, C.M., S.G. RAZAFIMANDIMBISON, L. BARRABÉ, J.G. JARDIM & M.R.V. BARBOSA (2017). Eumachia expanded, a pantropi- cal genus distinct from Psychotria (Rubiaceae, Palicoureeae). Candollea 72 : 289-318. In English, English abstract. DOI: http://dx.doi.org/10.15553/ c2017v722a6 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 combina- tions in Eumachia and two new synonymies for Neotropical names, and 11 names from various regions are lectotypified. Keywords RUBIACEAE – Palicoureeae – Psychotrieae – Chassalia – Eumachia – Mapouria – Margaritopsis – Psychotria – Readea – Nomenclature Addresses of the authors : CMT : Missouri Botanical Garden, P.O. Box 299, St. Louis MO 63166-0299 USA. E-mail : [email protected] SGR : Department of Botany, Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, Sweden. LB : Institut Agronomique néo-Calédonien (IAC), équipe SolVeg, BP A5, 98848 Nouméa, New Caledonia. JGJ : Instituto de Humanidades, Artes e Ciências, Campus Jorge Amado, Universidade Federal do Sul da Bahia, Itabuna, BA 45613-204, Brazil. MRB : Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, Caixa Postal 5065, 58051-970 Cidade Universitária, João Pessoa, PB, Brazil. Submitted on March 15, 2017. Accepted on June 14, 2017. First published online on July 20, 2017. ISSN : 0373-2967 – Online ISSN : 2235-3658 – Candollea 72(2) : 289-318 (2017) © CONSERVATOIRE ET JARDIN BOTANIQUES DE GENÈVE 2017.