Molecular systematics of the Asteriscus alliance (Asteraceae : Inuleae) I:Evidence from the internal transcribed spacers of nuclear ribosomal DNA

The Asteriscus alliance comprises three genera (Asteriscus, Ighermia, and P allenis) restricted to Macaronesia and the Mediterranean basin. This allian ce is a member of the tribe Inuleae where it forms a distinct morphological group with low chromosome numbers (n = 5-7). The taxonomic boundaries of t he three genera have been controversial, although previous morphological cl adistic analyses support the monophyly of each genus. Phylogenetic comparis ons of most taxa in the alliance and seven other genera of Inuleae were con ducted using ITS sequences. Parsimony analyses support the monophyly of the Asteriscus alliance and identify four lineages. One group has two species (P. hierochuntica and P. maritima), and two lineages are monotypic (P. spin osa and A. aquaticus). The fourth lineage includes the remaining 10 taxa of the Asteriscus alliance. Neither Asteriscus nor Pallenis, as currently def ined, is monophyletic, and Ighermia is sister to the largest Asteriscus cla de. All taxa distributed in Macaronesia, the arid African-Mediterranean bas in, the Sahara region, and the Middle East (except I! hierochuntica) are pa rt of the largest lineage. At least two independent colonizations from nort hern Africa have occurred in Macaronesia, one involving A. schultzii and th e second including the remaining five taxa endemic to the Cape Verde and th e Canary Islands. The derived position of these endemics in the ITS tree su ggests a recent colonization of the Macaronesian Islands from northern Afri ca. The ITS phylogeny is incongruent with previous morphological cladograms of the Inuleae because Buphthalmum and Xerolekia are not sister to the Ast eriscus alliance.