Abstract
A recent review of Bignoniaceae for the "Catalogue of the vascular plants of Madagascar" has revealed new species in most of the genera present on the island. We provide descriptions of four new species in the genus Ophiocolea H. Perrier, a genus that is endemic to the Malagasy region: Ophiocolea ambrensis Callm. & Phillipson, Ophiocolea darainensis Callm., Phillipson & Nusb., Ophiocolea pauciflora Callm., Phillipson & Razan. and Ophiocolea ratovosonii Callm. & Phillipson. Field photographs and line drawings are provided for each of these four new species. Two species described previously, Ophiocolea decaryi H. Perrier and Ophiocolea velutina H. Perrier, are lectotypified. For all six treated species, we provide a short discussion on morphological affinities and eco-geography, and perform a conservation threat analysis based on the IUCN Red List Categories and Criteria.