Some distinctive new species of Psychotria (Rubiaceae, Psychotrieae) from Madagascar

Psychotria L. (Rubiaceae, Psychotrieae) is an unusually species-rich genus in Madagascar. Recent botanical explorations here have found a number of undescribed species, and some unusual morphological structures for this genus. Here ten new Psychotria species from Madagascar are formally described: Psychotria ambatovensis C.M. Taylor, Psychotria antilahimenae C.M. Taylor, Psychotria birkinshawiana C.M. Taylor, Psychotria davisiana C.M. Taylor, Psychotria eumachioides C.M. Taylor, Psychotria hamifera C.M. Taylor, Psychotria mutabilis C.M. Taylor, Psychotria notopleuroides C.M. Taylor, Psychotria palifera C.M. Taylor, and Psychotria razafimandimbisonii C.M. Taylor. Unusual morphological features of some of these species include a prostrate habit, deeply retuse leaves, and enlarged, persistent, funnelform stipules. Assessment of the conservation status of these using IUCN Red List categories finds four of them "Vulnerable" and six "Endangered".