XVI International Botanical Congess

The Zingiberales is a tropical group of monocotyledons that includes eight recognized families. The order is considered by most taxonomists and phylogenists to be a monophyletic lineage of plants, but the phylogenetic relationships between genera are not clearly understood. The tracheary elements in the family Zingiberaceae were examined to characterize the diversity of structure and to better understand the phylogenetic relationships among related taxa. The distribution, size and specialization of tracheary elements in roots, stems and leaves of 62 species representing 28 genera were studied. The pit membranes in perforation plates and lateral walls of vessel members were also studied with both scanning and transmission electron microscopy. The presence and condition of pit membranes depended upon the developmental stage, but mature vessel elements lacked membranes at maturity.