A taxonomic synopsis of unifoliolate continental African Vepris (Rutaceae)

Summary Descriptions and illustrations are presented for three new species to science, Vepris udzungwa Cheek , V. lukei Cheek (both Udzungwa Mts, Tanzania), and V. robertsoniae Q.Luke & Cheek (SE Kenyan kaya forests), in the context of a synoptic taxonomic revision and with an identification key to all the known unifoliolate taxa of Vepris in continental Africa. The new species are described and illustrated, while the remaining 10 taxa are given skeletal taxonomic treatments (lacking descriptions). One widespread species in montane eastern Africa is renamed as V. simplex Cheek because its previous name, V. simplicifolia (Engl.) Mziray, is predated by V. simplicifolia Endl. (basionym of Sarcomelicope simplicifolia (Endl.) T.G.Hartley, a widespread species of Australia, Lord Howe and Norfolk Islands, and of New Caledonia). The new combination Vepris hanangensis var. unifoliolata (Kokwaro) Cheek is made. Full or provisional conservation assessments are presented for all species using the IUCN 2012 standard. Of the 13 taxa, nine are considered threatened or near threatened, of which one is Near Threatened, three are Vulnerable, two Endangered, and three Critically Endangered, with two of the latter, both of the Uluguru Mts of Tanzania, possibly extinct globally, although not yet assessed on the IUCN Red List.