Luke, W. R. Q. | bioRxiv Science

bioRxiv2022

A taxonomic synopsis of unifoliolate continental African Vepris (Rutaceae) with three new threatened forest tree species from Kenya and Tanzania

Descriptions and illustrations are presented for three new species to science, Vepris udzungwa Cheek, V. lukei Cheek (both Udzungwa Mts, Tanzania) and V. robertsoniae Cheek & Q. Luke (SE Kenyan kaya forests) in the context of a synoptic taxonomic revision, with an identification key to all the known unifoliolate taxa of Vepris in continental Africa. The remaining species are given skeletal taxonomic treatments (lacking descriptions). One widespread species in montane eastern Africa is renamed as Vepris simplex Cheek because its previous name, Vepris simplicifolia (Engl.)Mziray is predated by Vepris simplicifolia Endl. (basionym of Sarcomelicope simplicifolia (Endl.)T.G. Hartley, a widespread species of Australia, Lord Howe and Norfolk Islands, and of New Caledonia). Conservation assessments are presented for all species, or provisional conservation assessments are presented. Of the 13 taxa, 11 are considered threatened, of which six are VU, two EN and three CR, of which two are possibly extinct globally in the Uluguru Mts of Tanzania although not yet Red Listed on iucnredlist.org.

plant biology↗

bioRxiv2021

Lukea gen. nov. (Monodoreae-Annonaceae) with two new species of shrub from the forests of the Udzungwas, Tanzania & Kaya Ribe, Kenya.

A new genus, Lukea Gosline & Cheek (Annonaceae), is erected for two new species to science, Lukea quentinii Cheek & Gosline from Kaya Ribe, S.E. Kenya, and Lukea triciae Cheek & Gosline from the Udzungwa Mts, Tanzania. Lukea is characterised by a flattened circular bowl-shaped receptacle-calyx with a corolla of three petals that give the buds and flowers a unique appearance in African Annonaceae. Both species are extremely rare shrubs of small surviving areas of lowland evergreen forest under threat of habitat degradation and destruction and are provisionally assessed as Critically Endangered and Endangered respectively using the IUCN 2012 standard. Both species are illustrated and mapped. Material of the two species had formerly been considered to be possibly Uvariopsis Engl. & Diels, and the genus Lukea is placed in the Uvariopsis clade of the Monodoreae (consisting of the African genera Uvariodendron (Engl. & Diels) R.E.Fries, Uvariopsis, Mischogyne Exell, Dennettia Bak.f., and Monocyclanthus Keay). The clade is characterised by often conspicuous, finely reticulate quaternary nervation and incomplete or absent connective shields (in Annonaceae the connective shield is usually complete). Morphologically Lukea is distinct for its broad, turbinate, fleshy pedicel, a synapomorphy. It appears closest to the West African monotypic Monocyclanthus, sharing a trait unusual in the Annonaceae: the calyx in both genera forms a shallow bowl (calyx lobes are absent or vestigial), barely enclosing the base of the petals at anthesis, and persisting as a living, leathery disc at least until the fruit is mature. The placement of Lukea within the Uvariopsis clade is discussed.

plant biology↗