Abstract
Senecio pentanthus (Asteraceae, Senecioneae) has been previously placed in synonymy with Synotis triligulata. Our critical examination of herbarium specimens (including type material) and living plants of S. pentanthus demonstrates that it can be easily distinguished from Syn. triligulata by the leaf serration and the number of phyllaries and florets. We therefore reinstate the independent specific status of S. pentanthus and propose a new combination, i.e. Syn. pentantha. Lectotypification is made for Syn. pentantha herein. A key to all the known species in Syn. ser. Microglossae and Syn. vagans, a species placed in Syn. ser. Erectae but actually more closely similar to those in the former series, is provided.