Systematic Botany (2003), 28(2): pp. 270±292 q Copyright 2003 by the American Society of Plant Taxonomists Phylogenetic Relationships in the Commelinaceae: II. A Cladistic Analysis of rbcL Sequences and Morphology TIMOTHY M. EVANS,1,3 KENNETH J. SYTSMA,1 ROBERT B. FADEN,2 and THOMAS J. GIVNISH1 1Department of Botany, University of Wisconsin, 430 Lincoln Drive, Madison, Wisconsin 53706; 2Department of Systematic Biology-Botany, MRC 166, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013-7012; 3Present address, author for correspondence: Department of Biology, Hope College, 35 East 12th Street, Holland, Michigan 49423-9000 (
[email protected]) Communicating Editor: John V. Freudenstein ABSTRACT. The chloroplast-encoded gene rbcL was sequenced in 30 genera of Commelinaceae to evaluate intergeneric relationships within the family. The Australian Cartonema was consistently placed as sister to the rest of the family. The Commelineae is monophyletic, while the monophyly of Tradescantieae is in question, due to the position of Palisota as sister to all other Tradescantieae plus Commelineae. The phylogeny supports the most recent classi®cation of the family with monophyletic tribes Tradescantieae (minus Palisota) and Commelineae, but is highly incongruent with a morphology-based phylogeny. This incongruence is attributed to convergent evolution of morphological characters associated with pollination strategies, especially those of the androecium and in¯orescence. Analysis of the combined data sets produced a phylogeny similar to the rbcL phylogeny. The combined analysis differed from the molecular one, however, in supporting the monophyly of Dichorisandrinae. The family appears to have arisen in the Old World, with one or possibly two movements to the New World in the Tradescantieae, and two (or possibly one) subsequent movements back to the Old World; the latter are required to account for the Old World distribution of Coleotrypinae and Cyanotinae, which are nested within a New World clade.