Psychotriae (Rubiaceae) neocaledonicarum specierum nomenclator

The latest taxonomic treatment of the genus Psychotria s.l. (Rubiaceae) in New Caledonia is more than 50 years old, and the taxonomy continues to present problems due to the high number of published names. A nomenclatural study of New Caledonia Psychotria s.l. is thus provided here, in order to enumerate valid, unvalid and illegitime names for the two genera Psychotria s.s. and Margaritopsis C.Wright (previously placed under Psychotria s.l.). Herbarium specimens are designated to lectotypify names that are already published in the two genera Delpechia Montrouz. and Douarrea Montrouz. New names and new combinations are proposed to bring names into accordance with the International Code of Botanical Nomenclature for algae, fungi, and plants. The synonymy of several specific and varietal names is provided; the correct names for 59 accepted species are retained for Psychotria s.s. and three for Margaritopsis. However, four species names of uncertain placement (incertae sedis) remain. It is estimated that the species richness of both genera occurring in New Caledonia should be increased to 85 species, due to the discovery of undescribed species found in herbaria and during fieldwork.