What is Potentilla? A phylogeny-based taxonomy for Potentillinae (Rosaceae)

Abstract

Classification of Potentilla L. has varied considerably through time. Some authors have collapsed all of the Potentilleae tribe into a single genus, while others have divided it into more than 20 genera. All those classifications, except for the one that collapsed them all, have rendered the genus Potentilla polyphyletic. We discuss Potentilla from a phylogenetic perspective in order to achieve a reasonable classification in which Potentilla is based on a clade (monophyly). Other criteria are taken into account, namely: history, phylogenetic stability, gene flow, information content and ease of identification. All previously described genera in Potentillinae are briefly discussed and assigned to major clades. In order to do this, it was necessary to designate types for: Fraga Lapeyr., Trichothalamus Spreng., and Dactylophyllum Spenn. We discuss seven scenarios, representing the effects of classifying Potentilla at the seven major clades in Potentillinae, and conclude that the most supported and least disruptive is to classify Potentilla as the clade comprising all of Potentillinae excluding the Anserina clade.