The Gilbertiodendron ogoouense species complex consists of 14 tree species. Eight species are here newly described and one is here reinstated: G. bambolense Burgt; G. breteleri Burgt; G. ebo Burgt & Mackinder; G. ecoukense (Pellegr.) Burgt; G. maximum Burgt & Wieringa; G. minkebense Burgt & Estrella; G. quinquejugum Burgt; G. scutatum Wieringa & Estrella and G. sulfureum Burgt. Five species in the complex were already recognised as accepted: G. brachystegioides (Harms) J. Léonard; G. klainei (Pierre ex Pellegr.) J. Léonard; G. newberyi Burgt; G. ngouniense (Pellegr.) J. Léonard and G. ogoouense (Pellegr.) J. Léonard. All 14 species are medium-sized or large trees of evergreen rain forest on well-drained or periodically inundated soil, at 0 – 900 m altitude. Each of the 14 species is distributed in one or more of the following Central African countries: Cameroon, Equatorial Guinea, Gabon, Congo (Brazzaville), Angola (Cabinda) and Congo (Kinshasa). Included are a key, a table comparing the main morphological characters, illustrations drawn to the same scale and distribution maps of all species. The conservation status of all species is assessed according to IUCN categories and criteria: G. maximum is classified as Critically Endangered, G. ebo and G. newberyi as Endangered, G. breteleri, G. klainei, G. minkebense, G. ngouniense and G. scutatum as Vulnerable, and the remaining six species as Least Concern.
- new species