A matter of warts: a taxonomic treatment for Drypetes verrucosa (Putranjivaceae, Malpighiales) and a new cauliflorous species from Cameroon and Nigeria, D. stevartii

Abstract

Background and aims – Specimens of a new tree species in the genus Drypetes (Putranjivaceae) distributed in Cameroon and eastern Nigeria, D. stevartii, were associated with D. verrucosa, another tree species endemic to Gabon, due to its warty fruits and to the overall morphological resemblances of both species. Material and methods – The present study is based on the study of 20 gatherings of D. verrucosa and 26 gatherings of D. stevartii. Morphological observations on herbarium specimens belonging to the new species and D. verrucosa were carried out in order to describe them. Key results – This treatment includes the detailed descriptions of these two species, the typification of their names, a comparative table summarizing their main morphological differences, an identification key, photographs of both, as well as information about their distribution, habitat, and phenology. Preliminary IUCN Red List assessments show that both D. verrucosa and D. stevartii are ‘Near Threatened’ species.