Phylogeny of southern hemisphere Compositae-Anthemideae based on nrDNA ITS and cpDNA ndhF sequence information

Abstract

Twenty-nine genera of the tribe Anthemideae (Compositae) (111 genera, ca. 1,800 species) are either restricted to or have their distributional centre in the S hemisphere. We here present a phylogenetic study based on nrDNA ITS and cpDNA ndhF sequence variation for a complete generic sampling of this S hemisphere group of the tribe with its paramount importance for the understanding of the evolutionary history of this plant group. Our results corroborate the paraphyletic nature of the S hemisphere group of Anthemideae as a whole and of the four subtribes (Ursiniinae, Gonosperminae, Thaminophyllinae, Matricariinae) erected by Bremer and Humphries (1993) to accommodate its members. We further show that the genus Osmitopsis and the Cotula- group hold a basal position in the tribe. Members of the subtribe Ursiniinae (that is characterised by the possession of anthers with polarised endothecial tissue) form a paraphyletic group that may, together with a strongly supported monophyletic group around the genus Pentzia, contain the sister group(s) of the Asian and Mediterranean clades of the tribe. As a consequence of the non-monophyletic nature of the subtribes according to Bremer and Humphries (1993), we discuss an alternative generic grouping of the S hemisphere Anthemideae.