The Zingiberales are a group of entirely tropical monocots that includes eight families, 92 genera, and about 2,000 species. The four "banana-families" (Musaceae, Lowiaceae, Strelitziaceae, and Heliconiaceae) share the primitive feature of five or six fertile stamens the four "ginger-families" are similar in the single fertile anther and four or five highly modified staminodia. The Zingiberales are found on all major continents with tropical climates. While Marantaceae, Zingiberaceae, and Costaceae are pantropically distributed, Musaceae is found only in Southeast Asia and Africa, Strelitziaceae only in Africa and the Americas, and Heliconiaceae only in the Americas and Melanesia. The two families most restricted in distribution, Lowiaceae and Cannaceae, are found only in Southeast Asia or the Americas, respectively. The historical geographic distributions of the families were reconstructed in combination with dating events based on evidence from the fossil record and molecular sequence data. The common ancestor of the Zingiberales most likely originated around 110 mya with six of the eight families established by the end of the Cretaceous. The Zingiberales originated in tropical America and Southeast Asia with subsequent dispersals into Africa. The current distribution of the Zingiberales is a product of numerous secondary and tertiary dispersal events between the major tropical regions of the world. The phylogenetic diversification and biogeographic dispersal of the Zingiberales was in part driven by the evolutionary radiation and diversification of their associated animal pollinators, which include bats, birds, non-flying mammals, and insects. Six of the eight families of the Zingiberales contain taxa specialized for pollination by vertebrates, which may be the primitive state in the order, and two families are exclusively vertebrate-pollinated. Pollination by insects also occurs in six families with one, or possibly two, families exclusively specialized for insect visitors. The evolution of these diverse pollination systems have resulted in the wonderful diversity of this widespread order of tropical flowering plants.

This presentation is suitable for scientific but understandable to a general audience heliconia growers.

The pantropical Zingiberaceae is the largest family in the order Zingiberales with 53 genera and over 1200 species. Classifications of the family first proposed in 1889 and refined by others since that time recognize four tribes (Globbeae, Hedychieae, Alpinieae, and Zingibereae) based on morphological features, such as number of locules and placentation in the ovary, development of staminodia, modifications of the fertile anther, and rhizome-shoot-leaf orientation. New phylogenetic analyses based on DNA sequences suggest that at least some of these morphological traits are have evolved several times and three of the tribes are not "natural." The African genus Siphonochilus and Bornean genus Tamijia are basal clades. The former Alpinieae and Hedychieae for the most part are monophyletic taxa with the Globbeae and Zingibereae included within the latter. The results of these phylogenetic investigations have been used to propose a new classification of the Zingiberaceae that recognizes four subfamilies and four tribes: Siphonochiloideae (Siphonochileae), Tamijioideae (Tamijieae), Alpinioideae (Alpinieae, Riedelieae), and Zingiberoideae (Zingibereae, Globbeae). Morphological features congruent with this classification and the taxonomic status of various monotypic genera will be discussed.

Dr. W.J. Kress joins us from The Smithsonian Institution in Washington, DC.

Dr. W. John Kress was born in Illinois and received his education at Harvard University (B. A., 1975) and Duke University (Ph. D. 1981) where he studied tropical biology, ethnobotany, and plant systematics. Since then he has traveled to tropical areas around the world studying and collecting heliconias, gingers, and bananas. Before coming to the Smithsonian Dr. Kress was the Director of Research at the Marie Selby Botanical Gardens in Sarasota, Florida, from 1984 to 1988. Currently he is Curator and Research Scientist as well as Chairman of the Department of Botany at the National Museum of Natural History, Smithsonian Institution. He is a Fellow of the American Association for the Advancement of Science and currently Executive Director of the Association for Tropical Biology and Conservation.

Dr. Kress’ research interests focus on the evolution and relationships of tropical plants, especially Heliconia, gingers, and relatives. His field studies are concentrated on the evolution of breeding and pollination systems in plants, genetic variation and speciation in tropical angiosperms, and forest fragmentation and conservation of tropical ecosystems. Among his scientific and popular papers on tropical botany are his two books entitled "Heliconia: An Identification Guide,” published by the Smithsonian Institution Press, and “Heliconias – Las Lamaradas de la Selva Colombiana,” published in Bogotá, which include information on the botany and horticulture of these tropical plants. “A New Century of Biology,” co-edited with Gary Barrett and recently translated into Japanese, contains essays by some of the country’s leading scholars on the past, present, and future of the biological sciences. Dr. Kress’ most recent publication is “A Checklist of the Trees, Shrubs, Herbs, and Climbers of Myanmar,” which is the first comprehensive treatment of the plants of that country in decades. Dr. Kress is an Adjunct Professor of Biology at Duke University in North Carolina and George Washington University in Washington, DC.