Résumé
Background and aims -Riverine habitats along the Sanaga River in Cameroon were until recently little-explored by botanists, although they are facing increasing threats, notably from the construction of hydroelectric dams. Recent botanical inventories in the area have led to the discovery of several taxonomical novelties, including a new species of Phragmanthera (Loranthaceae) that is described here. Material and methods -This paper is based on field studies and examination of herbarium collections of the new species and its relatives. Classic practices of herbarium taxonomy have been applied. The conservation status of the new species is assessed following the IUCN Red List Categories and Criteria. Key results -Phragmanthera bidaultii sp. nov. is identified by its non-septate anthers (a unique character in the genus), by the patent to reflexed corolla lobes with the apex thickened into a conical appendage, and by its relatively narrow leaves, initially with sparse rufous barbellate hairs but soon becoming glabrescent on both sides. It has a very restricted distribution along the Sanaga River in Cameroon, where it grows in riparian forest, and it is assessed as Endangered (EN).