The generic concept of Lotononis (Crotalarieae, Fabaceae): Reinstatement of the genera Euchlora, Leobordea and Listia and the new genus Ezoloba

Lotononis is a large and taxonomically complex genus of the tribe Crotalarieae, with the majority of its species occurring within southern Africa. In this study, sequence and morphological data of the rare Lotononis macrocarpa was added to existing data matrices for the Crotalarieae and these were re-analyzed using both parsimony and model-based (Bayesian) analyses. Molecular systematic data (nrITS and rbcL) indicated that Lotononis is polyphyletic, with Lotononis sect. Euchlora as sister to Bolusia and Crotalaria and with L. macrocarpa close to the 'Cape' group of the Crotalarieae. As a result, the genus Euchlora is here reinstated and the new genus Ezoloba is described herein to accommodate the anomalous L. macrocarpa. Ezoloba is distinct in its 5+5 anther configuration, exceptionally large fruit, paired stipules, minutely serrate bracts and the presence of bracteoles. Within the remaining species of Lotononis, both combined and separate analyses of the morphological and sequence datasets revealed three strongly supported clades corresponding largely to clades recovered in previous cladistic analyses based on morphological, chemical and cytological data. These are here recognised at the generic level as Laotians s.str., Leobordea and Listia and the necessary new name combinations are formalised. Characters supporting these generic re-alignments are discussed and a key to the 16 genera now recognized in the tribe Crotalarieae is presented.