Notes on <i>Sericanthe</i> (Rubiaceae) from Central Africa, including a new combination and a new species from Cameroon: <i>Sericanthe owonoana</i> sp. nov.

Abstract

Abstract The genus Sericanthe (Rubiaceae—tribe Coffeeae DC.) included, at the time of writing, 23 species in tropical Africa, with a centre of diversity in the Lower Guinea domain. In the present paper, a new species, Sericanthe owonoana Sonké, Cheek &amp; O.Lachenaud sp. nov., is described and illustrated; it resembles S. auriculata (Keay) Robbr. in its densely parallel tertiary leaf veins, but differs by the acute to obtuse (vs. cordate to auriculate) leaf base, and smaller fruits, 1.2–1.5 cm long, with 1–2 seeds only [vs. (1.8–)3–6 cm long, with 2–5 seeds in each locule]. The new species is endemic to the highlands of western Cameroon and is assessed as Vulnerable following IUCN categories and criteria. The two varieties of Sericanthe testui (N.Hallé) Robbr. are here considered as separate species, hence the new combination S. pseudosalacia (N.Hallé) O.Lachenaud &amp; Sonké comb. nov. Previous confusions are corrected, as a result of which the range of S. pseudosalacia and S. roseoides (De Wild. &amp; T.Durand) Robbr. is extended to Cameroon and that of S. raynaliorum (N.Hallé) Robbr. to the Democratic Republic of the Congo. Sericanthe testui is no longer recorded from the latter country and S. rabia Sonké &amp; Robbr. is now restricted to Gabon. New records of S. lowryana Sonké &amp; Robbr. from Gabon and Equatorial Guinea, of S. petitii (N.Hallé) Robbr. from Equatorial Guinea, and of S. roseoides from Gabon are also presented. As a result of these changes, Sericanthe currently includes 25 species, of which 13 (plus an imperfectly known one) occur in Lower Guinea. A new dichotomic key to the species from this area is also presented.