Phylogenetic Affinities of South American Anemone (Ranunculaceae), including the Endemic Segregate Genera, Barneoudia and Oreithales

Abstract

This study tests the phylogenetic affinities of 11 South American species of Anemone s.l., including the closely related endemic segregate genera Barneoudia and Oreithales. We analyzed combined sequence data (chloroplast atpB‐rbcL spacer and nuclear ITS regions) for 51 species of Anemone s.l., using both likelihood and cladistic methods. The segregate genera, Oreithales and Barneoudia, nest within Anemone and are included in a clade (subgenus Anemone, sect. Pulsatilloides) consisting largely of South American taxa (Anemone sellowii, Anemone helleborifolia, and Anemone rigida) and other Southern Hemisphere species (e.g., Anemone caffra, Knowltonia vesicatoria, and Anemone crassifolia). As reported previously, Anemone antucensis (Chile and Argentina) is in a separate clade (subgenus and section Anemonidium) and is sister to Anemone tenuicaulis (New Zealand). Anemone multifida, Anemone triternata, and Anemone decapetala are embedded in a clade (subgenus and section Anemone) consisting largely of North American taxa. The tetraploid, Anemone multifida, was found in two separate, highly supported clades in the nuclear and chloroplast trees, suggesting a hybrid origin. Both sections Pulsatilloides and Anemonidium suggest that anemones originated in the Northern Hemisphere and subsequently spread to the Southern Hemisphere, a pattern found in common with other members of Ranunculaceae. Preliminary suggestions are offered for the reclassification of Anemone.