Parsimony analyses were conducted using a four-gene data set (rbcL, atpB, 18S rDNA, and 26S rDNA; over 8000 bp/taxon) for genera of early-diverging eudicots and appropriate placeholders for core eudicots using basal angiosperms as outgroups (60 genera total). The strict consensus of two shortest trees reveals a well-supported Ranunculales as sister to the remainder of eudicots, followed by Proteales, Sabiaceae + Buxaceae + Didymeliaceae + Trochodendraceae, and core eudicots. However, the clade of Sabiaceae + Buxaceae + Didymeliaceae + Trochodendraceae receives support < 50%. Within Ranunculales, most relationships receive support > 50%. Euptelea is sister to the remainder of the clade. Papaveraceae are the subsequent sister to the remaining Ranunculales. Lardizabalaceae and Circaeasteraceae form a clade that is sister to Menispermaceae and a clade of Ranunculaceae + Berberidaceae. Although our analyses provide additional support for relationships within Ranunculales, relationships among the groups of early-diverging eudicots are still unclear. Resolving these relationships will be a difficult task, requiring the sequences of still additional genes.

Key words: 18S rDNA, 26S rDNA, atpB, early-diverging eudicots, phylogeny, rbcL