RBCL SEQUENCES SUPPORT EXCLUSION OF RETZIA, DESFONTAINIA, AND NICODEMIA FROM THE GENTIANALES

The taxonomic positions of Retzia, Desfonlainia, and Nicodemia have be en much discussed, and all three genera have been included in Loganiac eae (Gentianales). We have made a cladistic analysis of rbcL gene sequ ences to determine the relationships of these taxa to Gentianales. Fou r new rbcL sequences are presented; i.e., of Retzia, Desfontainia, Die rvilla (Caprifoliaceae), and Euthystachys (Stilbaceae). Our results sh ow that Retzia, Desfontainia, and Nicodemia are not closely related to Loganiaceae or the Gentianales. Retzia is most closely related to Eut hystachys and is better included in Stilbaceae. The positions of Desfo ntainia and Nicodemia are not settled, but Desfontainia shows affinity for the Dipsacales s.l. and Nicodemia for the Lamiales s.l.