9419997 Baum The plant order Malvales contains ca. 5000 species of mainly tropical plants including several of economic importance (cotton, chocolate, okra, hibiscus). This study by Dr. David Baum of Harvard University and his colleague Dr. William Alverson will employ molecular techniques and analyses of plant morphology to study the evolution of the order, and in particular the phylogeny of certain groups at three nested levels. The placement of the order Malvales within the major dicot radiation of flowering plants; the placement of the family Bombacaceae (the kapok family) within the order; and relationships among the tribes and genera of Bombacaceae, are the three levels of emphasis. The molecular studies will involve the determination of DNA sequences from representative species of Bombacaceae and related Malvaceae, Tiliaceae, and Sterculiaceae, with emphasis on several chloroplast genes. In parallel the genera of Bombacaceae and relatives in the other three families will be studied for morphological characteristics, and the combined datasets will be used to infer phylogenetic relationships among the taxa. The resulting phylogenetic framework can be used to explain the great diversity of floral form within Bombacaceae and to account for evolutionary shifts in chromosome number and for geographical migrations through time. ??
