Phylogeny and Reclassification of Anemone (Ranunculaceae), with an Emphasis on Austral Species

Previous phylogenies based on molecular data indicated that segregate genera from both the Northern and Southern Hemispheres (Hepatica, Palsatilla, Knowltonia, Oreithales, and Barncoudia) are embedded within Anemone and should be subsumed within the genus. Based on a new phylogeny that substantially increases the sampling of the austral anemones (especially from Africa), we present a formal reclassification of Anemone s. 1. We analyzed combined sequence data (chloroplast atpB-rbcL spacer and nuclear ITS regions) for 55 species of Anemone s. I., using Bayesian inference, maximum likelihood, and maximum parsimony. The segregate genera, Oreithales and Barneoudia, nest within Anemone and are included in a well supported clade (subgenus Anemone, section Pulsatilloides) consisting largely of Southern Hemisphere species. The Mexican A. mexicana is sister to all remaining members of section Pulsatilloides, which consists of two clades: a poorly supported South American and Tasmanian clade (A. sellowii, A. helleborifolia, A. rigida, Barneoudia and Oreithales species, and A. crassijolia) and a highly supported southern African clade including nine species of Knowltonia and eight species of Anemone. Anemone antucensis Argentina) falls in a separate clade (subgenus and section Anemonidium) that is sister to A. tenuicaulis (New Zealand). Anemone thomsonii (eastern Africa) and A. somaliensis (Somalia) are in a clade (subgenus and section Anemone) composed largely of Northern Hemisphere species. Anemone somaliensis is further associated with other Mediterranean tuberous anemones in subsection and series Anemone (A. coronaria, A. hortensis, and A. pavonina). The topology of both sections Pulsatilloides and Anemonidium suggest that anemones originated in the Northern Hemisphere and subsequently spread to the Southern Hemisphere, a pattern that is shared with other members of Ranunculaceae. We present a formal reclassification of Anemone s. I., including the following new combinations and taxa of Anemone subgenus Anemone: subsections Alchemillifoliae, Anemonanthea, Barneoudia, Crassifoliae, Helleborifoliae, Kilimansharicae, Mexicanae, Oreithales, Rigidne, and Sellowii; series Carolinianae of subsection Anomie; plus the new combination Anemone balliana (= Barneoudia balliana).