Molecular Systematics of the Asteriscus Alliance (Asteraceae: Inuleae) II: Combined Nuclear and Chloroplast Data

Abstract

Phylogenetic relationships were assessed for 14 taxa in the Asteriscus alliance, a group of three genera within the tribe Inuleae. Species of Asteriscus, Ighermia, and Pallenis occur in desert and coastal habitats throughout the Mediterranean and Middle East, with several species endemic to Macaronesia. Sequence data from the external and internal transcribed spacers of the nuclear ribosomal DNA and from the chloroplast gene ndhF were obtained for all taxa. Analysis of individual and combined data sets support a monophyletic Pallenis but indicate that Asteriscus, as currently delimited, is paraphyletic. Reassignment of Ighermia to its former status as a species of Asteriscus allows Asteriscus to be monophyletic as well. Multiple, independent dispersal events between the continent and Macaronesian islands are required to explain the current distribution of taxa. In general, the island endemics are more derived than continental taxa, but the ultimate origin of the alliance remains unclear.