Voacanga madureirae (Apocynaceae), a new species from Atlantic Central Africa

A new species of Apocynaceae from Atlantic Central Africa, Voacanga madureirae Paiva, O.Lachenaud & Covelo, is mapped, described and illustrated. It occurs on the Gulf of Guinea islands of Príncipe (São Tomé and Príncipe) and Bioko (Equatorial Guinea) and in the highlands of western Cameroon. The new species differs from other African Voacanga by its calyx distinctly exceeding the corolla (vs shorter or at most equalling it). It is further separated from V. chalotiana Pierre ex Stapf by the presence of a row of colleters in the upper half of the calyx (not near the base) and from other Central African species by its syncarpous fruits and almost straight (not strongly twisted) corolla tube. It is assessed as Near Threatened according to IUCN criteria.