Taxonomy and phylogenetics of Cuviera (Rubiaceae–Vanguerieae) and reinstatement of Globulostylis with the description of three new species

Generic circumscriptions in tribe Vanguerieae (Rubiaceae) have been under discussion for a long time. Recent
molecular studies, while providing new insights, have not yet solved all the problems. In this study, the taxonomy
and phylogenetics of the genus Cuviera s.l. are investigated. On the basis of molecular and morphological evidence,
Cuviera is restricted to a group of ten West and Central African species. Globulostylis, previously included in
Cuviera, is reinstated as a distinct genus, with eight species from Central Africa. Both genera are revised; the
latter includes three new species (G. dewildeana, G. rammelooana and G. robbrechtiana) and two new combinations
(G. leniochlamys and G. uncinula). The close relationship of Cuviera s.s. and Globulostylis to Vangueriella is
shown. Six aberrant species (most from East Africa) are excluded from Cuviera, but further work is needed before
they can be confidently assigned to other genera.