The endemic plant species of Mt Kupe, Cameroon with a new Critically Endangered cloud-forest tree species, Vepris zapfackii (Rutaceae)

Abstract

We revise and update the records of strict and near-endemic species of Mt Kupe, Cameroon respectively from 31 strict endemics in 2004, to 25 today, and with near-endemic species 30, unchanged in number but with turnover. The changes result from new collections, discoveries and taxonomic changes in the last 16 years. While 15 of the provisionally named putative endemic species have now been formally published, a further 18 have not. The majority of the 30 near-endemic species (18) are shared with the adjacent Bakossi Mts, far exceeding the numbers shared with the more distant Mt Etinde-Mt Cameroon, Rumpi Hills and Ebo forest areas (sharing three near-endemic species each with Mt Kupe). We test the hypothesis that a further one of the provisionally named putative Mt Kupe species, Vepris sp. 1 from submontane forest near the summit, is indeed new to science. We compare it morphologically with the two other bicarpellate high altitude Cameroon Highland tree species Vepris montisbambutensis Onana and Vepris bali Cheek, concluding that it is a new undescribed species here named as Vepris zapfackii. The new species is illustrated, mapped and its conservation status assessed as Critically Endangered using the 2012 IUCN standard due to habitat clearance from agricultural pressures at its sole location which is unprotected. Vepris zapfackii and V. bali appear unique in African trifoliolate species of the genus in having opposite leaves. Vepris zapfackii differs in having hairy petiolules and midribs and petiolules with the blade decurrent distally, narrowing towards a winged-canaliculate base (vs glabrous and petiolule long, terete), and sparsely golden hairy pistillodes and a glabrous calyx (vs densely black hairy pistillodes, and sepals hairy).