Sonké, B. & O. Lachenaud (2016). Two new of Oxyanthus DC. (Rubiaceae) from Central Africa. Candollea 71: 173–180. In English, English and French abstracts.
Two new Rubiaceae species from Central Africa, Oxyanthus doucetii Sonké & O. Lachenaud and Oxyanthus lewisii Sonké & O. Lachenaud, are described and illustrated. Oxyanthus doucetii is endemic to Cameroon and is closely related to Oxyanthus unilocularis Hiern, from which it differs in the minute calyx teeth, the stems with glabrous internodes, the dorsally glabrous stipules, the flower buds with a shorter head, and the corolla lobes not or hardly acute at apex. Oxyanthus lewisii is sparsely distributed from Cameroon to eastern Democratic Republic of Congo, and is characterised by narrow fusiform fruits, glabrous stems, and leaves lacking domatia but sparsely pubescent on the nerves beneath. Both new species are assessed as “Vulnerable” according to IUCN Red List Categories and Criteria.