Notes on Tricalysia elmar sp. nov. (Rubiaceae, Coffeeae), and cloud forest of the Cameroon Highlands

Background and aims - This paper reports a further discovery in the context of a long-term botanical survey in the Cross River-Sanaga interval of west-central Africa, focussing on species discovery and conservation. Methods - Normal practices of herbarium taxonomy have been applied to study the material collected. The relevant collections are stored in the Herbarium of the Royal Botanic Gardens, Kew. London and at the Institute of Research in Agronomic Development - National Herbarium of Cameroon. Key results - Species new to science recently discovered from the cloud (submontane) forests of the Cameroon Highlands in Cameroon are reviewed. Most of these species are rare, highly localised, and threatened by habitat destruction. These discoveries increase the justification for improved conservation management of surviving habitat. Tricalysia elmar Cheek (Coffeeae-Rubiaceae) is described as an additional cloud forest species new to science. Its taxonomic position is discussed, and it is compared with similar species of the genus. Restricted so far to four locations, Mt Kupe, Bali Ngemba, Lebialem and Nta Ali, its conservation status is assessed as Endangered (EN B1+2ab(iii)) according to the 2012 criteria of IUCN.