Abstract
Background - The inventory of Cameroon's flora is far from complete and additional work is needed to document the country's extremely rich flora, and thus enhance its conservation. In this framework, botanical exploration was conducted between 2007 and 2011 in various regions of Cameroon and resulted in the discovery of several new national records and new species.Methods - Normal practices of herbarium taxonomy have been applied. For the endemic or subendemic species, a preliminary IUCN conservation has been proposed using the IUCN criteria.Results - A total of twelve taxa are recorded as new for the flora of Cameroon. Significant range extensions are reported for eight restricted-range species. A new species, Psychotria yaoundensis O. Lachenaud, endemic to Cameroon and only know from two rocky hills in the surroundings of Yaoundé, is described and illustrated. Additions to the flora of Equatorial Guinea (five species), Nigeria, Ivory Coast and the Democratic Republic of Congo (one species each) are also reported. Psychotria moliwensis and Vangueriopsis gossweileri are synonymised under P. fernandopoensis and V. rubiginosa, respectively.Conclusion - Many areas within Cameroon remain botanically poorly explored. Our exploration highlights the importance of the Rumpi Hills, Tchabal Mbabo, and the rocky hills around Yaoundé for plant conservation. Our data will help conservationists in determining areas highly valuable for conservation.