New and little-known Psychotria (Rubiaceae) from West Africa, and notes on litter-gathering angiosperms

Background - Five new species of Psychotria (Rubiaceae) from West Africa are described and illustrated, in the framework of a regional revision of the genus. Methods - Normal practices of herbarium taxonomy have been applied. Key results - Three of the new species, Psychotria baldwinii, P. tetragonopus and P. voorhoevei, are endemic to Liberia, while the other two, P. blydeniae and P. rubriceps, also occur in adjacent southwestern Cote d'Ivoire. The Ivorian endemic Psychotria copeensis, previously included in the synonymy of P. subobliqua, is separated as a distinct species. Psychotria blydeniae and P. tetragonopus are litterbin plants; we discuss this remarkable adaptation and its occurrence in various Angiosperm families in the African rainforests.