Addressing the Vepris verdoorniana complex (Rutaceae) in West Africa, with two new species

Abstract

Summary. Vepris verdoorniana (Rutaceae) has long been regarded as a widespread and variable species occurring from Guinea to Gabon. Recent evidence has shown that the original material from the type locality in Cameroon consists of two different species, V. verdoorniana in the strict sense, endemic to Lower Guinea (Cameroon, Gabon and C.A.R. in W-C Africa) and V. letouzeyi Onana, which was thought to occur from Guinea to Cameroon. In this paper we show that the West African (Upper Guinea) material previously referred to as V. letouzeyi/V. verdoorniana is separate morphologically from that in Cameroon (Lower Guinea). In fact the West African material referred to comprises two distinct species, here described as V. occidentalis Cheek & Onana (Guinea to Ghana, but probably extending to Benin) a tree of lowland marginal dry evergreen and semi-deciduous forest, and V. fer Cheek, a species restricted to four mainly lower submontane forest locations on iron substrates in Liberia and Sierra Leone (also Upper Guinea). Vepris occidentalis is here assessed as Least Concern due to its wide range and high frequency, whilst V. fer is assessed as Endangered due to the low number of locations and threats from iron ore mining projects. Both new species are illustrated and mapped.