Plukenetia kwangoensis sp. nov. (Euphorbiaceae, Acalyphoideae, Plukenetieae), a new species of Plukenetia L. sect. Hedraiostylus (Hassk.) Müll.Arg. from Democratic Republic of Congo

Plukenetia kwangoensis sp. nov., a new species from savannas of western Democratic Republic of Congo, is described and illustrated. The species belongs to Plukenetia sect. Hedraiostylus (Hassk.) Müll.Arg., an African and Asian section characterized by short styles, small dry capsules, small lenticular seeds, and foveolate pollen. It is morphologically most similar to P. africana Sond. from southern Africa, differing in its shorter petioles, absence of stipels at the petiole apex, leaf blades with narrowly acute bases and more numerous secondary veins, and shorter pistillate flower pedicels. The description of Plukenetia sect. Hedraiostylus is emended to encompass the new species’ erect habit and pinnately veined leaf blades; a key to the four species in the section is provided.