Phylogenetic Reconstructions and Two New Varieties in the Andropogon virginicus Complex (Poaceae: Andropogoneae)

Abstract

Phylogenetic reconstructions of the Andropogon virginicus complex were performed using Swofford's computer programs for maximum parsimony. Character state polarity is based on outgroup analysis of Andropogon sect. Leptopogon, to which the virginicus complex belongs. A pre- viously undetected synapomorphy justifies monophyly of this section. The data used in the recon- structions contain extensive homoplasy, and tree topology changes considerably with minor changes in the data. Nevertheless, the interrelationships of the taxa on the most parsimonious trees are largely concordant with the results of previous studies. These cladistic analyses do, however, sug- gest different evolutionary relationships for the subspecific taxa of A. virginicus and A. glomeratus, the two most complex species. As a consequence of these analyses, two new varieties, A. virginicus var. decipiens and A. glomeratus var. scabriglumus, are described. The Andropogon virginicus complex is a group of sexually reproducing perennials with a cen- ter of diversity on the Coastal Plain of the southeastern United States. Using an eclectic approach, combining phenetic and evolution- ary perspectives, I recognized 20 operational taxonomic units (OTUs) in the virginicus com-