A new species of the carnivorous genus Genlisea, endemic to inselbergs in Guinea, is described. Genlisea barthlottii differs from Genlisea stapfii by being considerably larger in all vegetative parts, the spur being longer than the lower lip and by long-stalked glandular hairs restricted to the upper part of the ovary. In West Africa three species of Genlisea occur: G. barthlottii, G. hispidula and G. stapfii.