PHYLOGENY OF THE RANUNCULACEAE BASED ON PRELIMINARY ATPB, RBCL AND 18S NUCLEAR RIBOSOMAL DNA-SEQUENCE DATA

The chloroplast genes atpB and rbcL and nuclear ribosomal 185 DNA were sequenced for 23 genera of the Ranunculaceae and two outgroup taxa (H ydrastis and Glaucidium). The three sequence data sets were combined a nd the resulting preliminary phylogenetic tree used to assess relation ships within the Ranunculaceae. The phylogeny strongly supports the mo nophyly of the family, with 26 substitutions, a bootstrap value of 98% and a decay index of > 7. Within the family, the T-type chromosome gr oup is basal and paraphyletic with respect to the larger R-type chromo some group. Within the T-type chromosome group, Coptis and Xanthorhiza from a monophyletic group and are basal to all other Ranunculaceae. O ther alliances previously proposed by taxonomists are confirmed: nella /Thalictrum/Isopyrum/Aquilegia/Semiaquilegia; Anemone/Clematis, Trautv etteria/Myosurus/Ranunculus; Aconitum/Delphinium; and Anemonopsis/Cimi cifugal/Actaea. Other groupings that could not have been predicted on the basis of traditional data include a clade consisting of Adonis and Trollius and the inclusion of Eranthis in a clade with Anemonopsis, C imicifuga, and Actaea. Nigella is weakly allied with a clade consistin g of Aconitum and Delphinium. The molecular sequence data are largely congruent with results based on cytology, phytochemistry, and micromor phology. Flower and fruit characters are homoplastic in relation to th e cladogram based on sequence data. The pattern of relationships based on sequence data supports the view that staminodia/petals and achenes have evolved independently several times within the Ranunculaceae.