Nectaropetalum camerunense (Erythroxylaceae), a new species from the Sanaga basin in Cameroon, with a key to the genus

Background and aims – This paper describes and illustrates a new species of Nectaropetalum (Erythroxylaceae) from the Sanaga River basin in Cameroon. The genus otherwise includes eight species: two in the Democratic Republic of the Congo, five in coastal areas of eastern and southern Africa, and one in Madagascar. Material and methods – The description of the new species is based on the study of 13 gatherings, field observations, and a comparison with available material of its congeners in BR and K. Its conservation status was assessed following the IUCN Red List Categories and Criteria.

Key results – The discovery is an important westwards range extension for the genus. Nectaropetalum camerunense sp. nov. most closely resembles N. acuminatum from Tanzania in vegetative characters, but differs by its shorter sepals and short thickened pedicels (vs sessile flowers). A key to the genus Nectaropetalum is presented.

The new species is endemic to the middle Sanaga basin in Cameroon, where it occurs gregariously in periodically flooded riverine forests. It is assessed as Endangered following IUCN Red List Categories and Criteria. This brings the total number of Sanaga basin riverine endemics to date to nine, all of which are currently facing significant threats from agriculture and the construction of hydroelectric dams.