9727000 Davis A PHYLOGENETIC ANALYSIS OF THE MONOCOTS BASED ON MOLECULAR AND MORPHOLOGICAL CHARACTER SETS The monocotyledons are one of the major groups of flowering plants (angiosperms). This is a diverse group of about 60,000 species that includes the grasses (wheat, maise, rice, and their many wild relatives), palms, and orchids. Although the monocot group is widely recognized as a natural (monophyletic) lineage within the flowering plants, many aspects of the history of divergence of the principal lineages within this group remain obscure. Support for several major lineagess is well established (e.g., the order Poales, which includes grasses and their relatives, and the order Zingiberales, which includes the gingers, the bananas, and their relatives), but there are major differences in the other higher-level groupings recognized by various comprehensive accounts of the monocots. Phylogenetic analyses based on variation in morphology and a variety of molecular characteristics, have yielded conflicting results which Dr. Davis' study will investigate using "total evidence" in which multiple character sets will be collected for exemplar species; these will be combined within a single data set and analyzed as a unit. Data sets to be analyzed include 1) morphology with features of anatomy, pollen structure, and seed development included, 2) DNA sequence variation from genes of the chloroplasts (rbcL) and mitochondria (atpA), and 3) additional character sets being generated by other cooperating investigators.
