Abstract
A new species of spiral ginger (Costus: Costaceae) from Gabon, Africa is described. Costus loangensis H. Maas & Maas is found in the coastal region on white sand soils under a tropical rain forest canopy. It is morphologically distinct from all other African species of Costus but shows some similarities in floral form with the savanna-inhabiting Costus spectabilis (Fenzl) K. Schum. and similarities in vegetative form with Costus ligularis Baker. Only one population of the new species is documented. Photographs of the new species are included as is a preliminary phylogeny indicating its position within the African Costaceae.