Phylogenetic relationships of Rutaceae: a cladistic analysis of the subfamilies using evidence from RBC and ATP sequence variation.

Sequence data for plastid rbcL and atpB from members of Anacardiaceae, Burseraceae, Cneoraceae, Meliaceae, Ptaeroxylaceae, Rutaceae, and Simaroubaceae were analyzed cladistically to evaluate the familial and subfamilial circumscriptions of Rutaceae. Taxa representing all subfamilies and tribes were sampled. The analysis shows that Rutaceae are paraphyletic, with Spathelia and Dictyoloma (Rutaceae), Harrisonia (Simaroubaceae), Cneorum (Cneoraceae), and Ptaeroxylon (Ptaeroxylaceae) forming a clade sister to all other Rutaceae. Circumscription of Rutaceae to include all of these taxa is recommended. This analysis indicates that Simaroubaceae and Meliaceae are the outgroups closest to Rutaceae. Correlation of the molecular phylogenies with biochemical data indicates that chemotaxonomic information is more reliable than fruit type as an indicator of familial and subfamilial circumscriptions. The subfamilial classification needs revision; none of the subfamilies of more than one genus is monophyletic.