Taxonomic revision of South African Memecylon (Melastomataceae—Olisbeoideae), including three new species

Earlier works recognised two South African species Memecylon bachmannii and M. natalense within M. sect. Buxifolia, but recent molecular analyses have revealed that M. natalense as previously circumscribed is not monophyletic and includes several geographically outlying populations warranting treatment as distinct taxa. In this revision we recognise five endemic South African species of which M. bachmannii and M. natalense are both maintained but with narrower circumscriptions, and M. kosiense, M. soutpansbergense and M. australissimum are newly described. Memecylon kosiense is localised in north-eastern KwaZulu-Natal (Maputaland) and is closely related to M. incisilobum of southern Mozambique. Memecylon soutpansbergense, from Limpopo Province, was previously confused with M. natalense but is clearly distinguished on vegetative characters. Memecylon australissimum occurs in the Eastern Cape (Hluleka and Dwesa-Cwebe nature reserves) and has relatively small leaves like those of M. natalense, but the floral bracteoles are persistent and the fruit is ovoid as in M. bachmannii. We further designate a lectotype for M. natalense, provide an updated key to the South African species of Memecylon, and provisionally assess the status of each species in accordance with International Union for Conservation of Nature criteria.

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