Keetia magassoubiana sp. nov. (Rubiaceae - Vanguerieae) a threatened evergreen forest climber of West Africa

Keetia magassoubiana Cheek, an evergreen rainforest climber, is described and illustrated from the Republic of Guinea, Sierra Leone, Liberia and Ivory Coast. Previously indicated as being close to but different from Keetia tenuiflora (Hiern) Bridson, it differs in the glossy black, glabrous, epidermis of the distal stem internodes, the first internode rarely with very sparse red adpressed hairs (vs epidermis pale white-brown, dense pale yellow spreading hairs) and abaxial leaf surface with domed domatia with a central aperture (vs domatia absent or obscure), the secondary stem leaf bases acute (vs obtuse to truncate), the bracts forming a laciniate sheath on the distal peduncle (vs two opposite triangular bracts), the pyrene surface honeycombed with pits (vs entire). The species was earlier included within Canthium multiflorum (Schum. & Thonn.) Hiern (now K. multiflora (Schum. & Thonn.) Bridson) in the Flora of West Tropical Africa second edition. An updated key is presented to the 16 species of the genus from West Africa. Keetia magassoubiana is provisionally assessed using the IUCN standard as Endangered EN B1ab(iii) due to only five of the recorded 14 locations having extant forest habitat, and because of ongoing threats of habitat clearance mainly for agriculture, but also mining.