Hibiscus fabiana sp. nov. (Malvaceae) from the Guinea Highlands (West Africa)

Hibiscus fabiana Cheek (sect. Furcaria, Malvaceae) is described from the Guinea Highlands of West Africa, and its taxonomic affinities and ecology are considered. Hibiscus fabiana has previously been confused with H. rostellatus but has red fleshy calyx ribs (vs not red and non-fleshy), the calyx surface is glabrous apart from 1-armed bristles (vs densely covered in minute white stellate hairs and bristles 2- 5-armed), the leaves 3(-5)-lobed, bases truncate to rounded (vs 5-lobed, cordate). The conservation status of the new species is assessed using the IUCN 2012 standard as Vulnerable. In the context of the recently discovered extinction of the Guinean endemic Inversodicraea pygmaea G.Taylor (Podostemaceae), we discuss the 30 new species to science discovered in Guinea since 2005, all but one of which are also range-restricted and threatened, usually by development or habitat loss. We consider it urgent to avoid their extinction, ideally with in situ conservation using an Important Plant Areas approach.