Revised treatment of Memecylon section Buxifolia (Melastomataceae) in Madagascar

Memecylon sect. Buxifolia R.D. Stone (Melastomataceae, Olisbeoideae) is a group of forest shrubs and small understory trees distributed from tropical East Africa ( Kenya and Tanzania) to eastern South Africa and with a disjunct occurrence in western and northern Madagascar. In a previous treatment, three endemic Malagasy species of this section were recognized: M. amplifolium R.D. Stone, M. buxifolium Blume (= M. perrieri Danguy), and M. multinode Jacq.-Fel. The present work describes and illustrates six new species from Madagascar belonging to this section: M. ambilobense R.D. Stone, M. angustatum R.D. Stone, M. leptophyllum R.D. Stone, M. minutifolium R.D. Stone, M. oblanceolatum R.D. Stone, and M. reductum R.D. Stone. With these revisions, the flora of Madagascar now holds nine species of Memecylon sect. Buxifolia, for which a formal taxonomic treatment is provided including a dichotomous key. The conservation status of each species is provisionally assessed in accordance with the IUCN Red List Categories and Criteria.