A re-evaluation of North American Tephroseris and Sinosenecio (Asteraceae: Senecioneae) based on molecular and micromorphological data

Abstract

The recent transfer of the Queen Charlotte island endemic, Senecio newcombei Greene (Senecioneae: Asteraceae), to the Asiatic genus Sinosenecio extends the biogeographic range of Sinosenecio to North America and introduces a large amphi-Beringian gap in the distribution of the genus. However, the closely related genus Tephroseris includes a number of North American species with distributions in the vicinity of S. newcombei. We provide molecular sequence data from the ITS region of nuclear ribosomal DNA and micromorphological data from anther endothecial cells that indicate S. newcombei is closely related to North American Tephroseris species. However, the overall relationship between Sinosenecio and Tephroseris remains unresolved, so that transfer of S. newcombei to Tephroseris is not proposed.Key words: Tephroseris, Sinosenecio, phylogeny, ITS, anther endothecial cells.