Sequences of nuclear ribosomal DNA ITS and ETS regions were used to examine phylogenetic relationships of Syringa and Ligustrum. Thirty samples were included in parsimony analyses, representing all major groups of these two genera. Two species of Fraxinus and one species of Jasminum were also included in analyses for rooting purposes. Species of series Vulgares (Syringa) and the monotypic series Pinnatifoliae (Syringa) are basal clades followed by a clade containing Ligustrum species and the remaining Syringa species. Species of Ligustrum form a well-supported clade, which is sister to a clade containing the rest of species of Syringa, including subgenus Ligustrina, and series Pubescentes and Villosae. All these groups are monophyletic. Parasyringa sempervirens is phylogenetically embedded within the Ligustrum clade, supporting its placement in Ligustrum. Our results indicate that Ligustrum is derived from within Syringa, suggesting that Syringa as traditionally circumscribed is paraphyletic. Berries are a synapomorphy of Ligustrum species, and the dehiscent berry of Parasyringa sempervirens is an evolutionary reversal to a capsule, which is characteristic of Syringa. The evolution of berries might have resulted in an accelerated speciation in Ligustrum.

Key words: ETS, ITS, Ligustrum, Oleaceae, paraphyly, phylogeny, Syringa