The generic status ofAnacolosa(Olacaceae) in Africa withA. deniseaea new species to science of Endangered submontane forest liana from Simandou, Republic of Guinea

Summary Anacolosa deniseae Cheek (Olacaceae) a submontane gallery forest canopy liana is described as a new species to science and assessed as Endangered using the IUCN 2012 standard due to threats of habitat destruction connected with mining. The roots smell of benzaldehyde when scraped, and the plant reproduces from root suckers. The species is restricted globally to two locations in the Loma-Man Highlands of the Republic of Guinea, all records but one being in the Pic de Fon Fôret Classé of the Simandou Range. We show that this and the only other continental African species ascribed to the genus Anacolosa, A. uncifera of DRC, Gabon & C.A.R., differ in so many architectural, floral and vegetative characters from the remaining species of the genus, which occur from Madagascar to the Western Pacific, including the type A. frutescens (S.E. Asia and Indo-China), that they clearly represent a separate genus. The African genus represented by these two species is unique within the Olacaceae (excluding Erythropalaceae) in being a climber (vs. shrubs or trees in Anacolosa sensu stricto ). Climbing in the two African species is achieved by perennial hook-like structures formed by a combination of five separate traits each of which is unknown elsewhere in the Olacaceae. We formally delimit and describe this new genus, discussing its characteristics, but in the absence of molecular phylogenetic data, refrain from naming it.