GENERIC BOUNDARIES IN THE SENECIONEAE

Summary Since the time of Bentham the traditional view of the Senecioneae has been that of one huge genus (Senecio) plus numerous segregate genera of varying degrees of distinctiveness, plus a few entities of uncertain affinities. Data have accumulated to support the exclusion of some genera from the tribe (e.g. Arnica, Liabum, Munnozia, Schistocarpha , etc.) and to tease botanists about the circumscriptions and affinities of others. Senecio sensu lato incorporates several semi‐distinctive natural assemblages that usually have been treated as sections or subgenera. The naturalness of these assemblages is generally acknowledged, as is the fact that the boundaries separating them are imprecise by whatever suites of characters are used to measure them. In several recent studies many segregate genera have been recognized, often with the circumscriptions derived from selected representative species. It is yet unclear that the recognition of numerous segregate genera provides a better taxonomy than treating the variation patterns as infrageneric taxa. A respectable case can be made for maintaining Senecio as a broad concept, at least until revisionary studies at the species level are carried out and the results subjected to critical analyses.