A revision of the Crepidorhopalon whytei complex (Linderniaceae) in eastern Africa

Abstract

The Crepidorhopalon whytei (Linderniaceae) species complex is revised using morphological analyses. Based primarily on variations in indumentum, floral morphology, corolla colour and seed morphology, four species are formally recognised within this group in eastern Africa. Crepidorhopalon whytei s.str. is widespread in the highlands of eastern Africa, extending from South Sudan and Ethiopia in the north through to western Tanzania in the south. A new combination in Crepidorhopalon is made for Lindernia flava (= C. flavus), which is confined to the Manica Highlands of the Mozambique-Zimbabwe border. Two new species are described, C. namuliensis which is known only from Mt Namuli in northern Mozambique and C. kwaleensis which is known only from the coastal lowlands of southeast Kenya. A fifth, imperfectly known species is documented from the Nguru Mountains of Tanzania where it is so far known from a single collection. Three names are lectotypified. The habitat requirements and distribution are documented and the extinction risk is assessed for each species. Crepidorhopalon flavus is assessed as globally Vulnerable and C. kwaleensis as globally Endangered, while C. namuliensis and C. whytei are currently considered to be of Least Concern, although the latter is declining markedly in parts of its range. The botanical importance of the key sites for the newly recognised taxa is discussed.