A taxonomic revision of the endemic New Caledonian genus Podonephelium Baill. (Sapindaceae)

The endemic New Caledonian genus Podonephelium Baill. has representatives in all of the archipelago's main vegetation types (maquis, dry forest, and humid evergreen forest) and occurs on each of its principal substrates (calcareous, ultramafic and volcano-sedimentary). Recent phylogenetic studies confirm its monophyly and indicate that it forms a clade with two other endemic genera, Gongrodiscus and Storthocalyx. Podonephelium is characterized by juvenile leaves that form a whip-like structure and fruit that dehisce longitudinally into two halves that contain a round black seed nearly entirely covered by a red arillode. As part of a collaborative effort to clarify the taxonomy of New Caledonian Sapindaceae, a revision of Podonephelium is presented based on examination of all available collections coupled with extensive field studies. Nine species are recognized, four of which are newly described (P. cristagalli, P. davidsonii, P. pachycaule, and P. plicatum) and one infraspecific taxon is elevated to the rank of species (P. gongrocarpum). A key to species is provided, along with descriptions, distribution maps, line drawings (for the new species and new combination), and risk of extinction assessments using the International Union for Conservation of Nature IUCN red list criteria.