Inter-familial relationships in the Ranunculidae based on molecular systematics

Abstract

Nucleotide sequences from the rbcL and atpB genes (chloroplast DNA) and 18S nuclear ribosomal DNA provide important new data with which to test previous hypotheses of inter-familial relationships in the angiosperm subclass Ranunculidae. Preliminary conclusions based on cladistic analysis of the combined molecular data sets for all three genes are broadly congruent with previous analyses based on rbcL data alone. The genus Euptelea, which has been placed traditionally among the ''lower'' Hamamelididae, is resolved as more closely related to ranunculids. Papaverales (represented by Pteridophyllaceae and Fumariaceae including Hypecoum) are strongly supported as a monophyletic group, and are resolved as basal to all other ranunculids (''core'' ranunculids) plus Euptelea. The monotypic genera Kingdonia and Circaeaster are placed as sister taxa and together are sister to Lardizabalaceae s.l. (including Sargentodoxa). The Lardizabalaceae- Circaeaster-Kingdonia clade is the sister taxon to Menispermaceae-Ranunculaceae- Berberidaceae. Menispermaceae is the sister taxon to Ranunculaceae and Berberidaceae.