A reconsideration of the Lower Guinean species of Sericanthe (Rubiaceae, Coffeeae), with four new species from Cameroon and Gabon

The genus Sericanthe was established and its species were revised 30 years ago by one of the authors. Intensive recent botanical collecting in Lower Guinea (mainly southern Cameroon, Equatorial Guinea and Gabon) has made a reconsideration of species in this area necessary. Revision of the newly collected Lower Guinean herbarium specimens of Sericanthe (twice as many as were available at the time of the first revision) has brought four new species to light, namely S. gabonensis and S. mpassa from Gabon, S. lowryana from Cameroon and S. rabia from Cameroon and Gabon. Distributional data are much augmented, and distributional maps of all species from the area are provided. Four species were reported to be newly recorded for at least one country. The occurrence of the novelties in the main diversity centre of the genus is discussed in the context of the chorology of the entire genus Sericanthe. A first estimation of the conservation status for the new species is given. A synopsis of the genus Sericanthe in Lower Guinea with a taxonomic key is provided. (c) 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169, 530554.