I owe my greatest appreciation to my major advisor Dr. Thomas Croat for his strong friendship, indispensable guidance, unlimited patience, tireless assistance, and good spirits, which benefited me greatly. His both herbarium and greenhouse collections, personal field observations, photographs, and type information on the genus Dracontium have laid the foundation for this study.

My other committee members provided valuable guidance throughout the course of this study. Mike Grayum has influenced me tremendously on almost every taxonomic decision I have made in this revision with his extraordinary knowledge and understanding of the Araceae and his keen vision of plant taxonomy. David Boufford has always been a great advisor since even before I started this revision. He has played a major role in my graduate career including the selection of an advisorship, the choosing of a dissertation topic, and the use of DELTA programs for this revision. As soon as I first arrived at St. Louis, P. Mick Richardson became the most important resource person for almost everything, including western culture and a much broader botanical world. I am grateful for his encouragement during many difficult times, especially for his advisorship during my precandidatoral years. Dr. Victoria Sork is highly appreciated for providing critical guidance and encouragement, especially during the first couple of years of my study at UM-St. Louis. I am very thankful to Dr. Bette Loiselle for her great patience and skilful guidance and assistance in both the field and the computer lab. Under her guidence, I produced all the distribution maps in this revision using the ArcView and ArcInfo programs with coordination data stored in TROPICOS. I am grateful to Dr. Ta-pei Cheng for serving on my committee as the on campus non-biology member. Very special thanks must go to Dr. George Yatskievych for his friendship and countless discussions on nomenclature, taxonomy and many other subjects. Special thanks also go to Dr. James Zarucchi, for whom I worked as a research assistant for the past three years, for his strong support and broad understanding and for his reading of an early draft of this revision. I would like also thank Drs. Ihsan Al-Shehbaz, Gordon McPherson, Josef Bogner, Wilbert Hettercheid and Julius Boos for reviews the manuscript and providing critical materials for my research. This revision owes its completion to the great assistance of Petra Malesevich, who was always available to help on almost any detailed problems I encountered. Her professional assistance and great patience are extraordinarily appreciated. Dr. Richard Keating contributed the detailed anatomical data for this study. Drs. Dan Nicolson and Fred Barrie provided great assistance to solve nomenclatural problems and partially read the manuscript. Eleanor Sauer helped with all Latin descriptions for new taxa. Dr. Peter Hoch, Simon Malcomber and Neil Snow helped me with cladistic analyses. Hong Song developed a database for this revision and provided great assistance in many other computer- related aspects. Alan Tucker assisted with editing computerized images. Kathy Upton provided excellent greenhouse assistance. Profs. Yizhen Xi and Valentina Tarasevich provided invaluable help with pollen studies. I am grateful to Drs. Douglas and Pamela Soltis and Qiuyun Xiang for the opportunity to study molecular aspects of the plants at Washington State University. Numerous people have kindly collected material in the field or from the greenhouse, or personally helped me in the field or in the herbarium, including Donna Atwood, John Banta, Gerardo Avalos, Dorothy Bay, Stephan Beck, Hans Boos, Germ

I am appreciative to the curators of the herbarium and the librarians of the Missouri Botanical Garden and to the professors and staff of the Biology Department of University of Missouri-St. Louis for the wonderful environment they provided for the completion of my study. I am also grateful to my fellow graduate students at UMSL, WU and SLU for their friendship, patience and many intellectual discussions. I extend my appreciation to the curators of AAU, B, BBS, BM, BR, CAY, CM, COL, CR, DUKE, EAP, ECON, F, FTG, G, GH, IAN, IBE, INB, INPA, JAUM, K, M, MEXU, MG, MO, MOL, NY, P, PMA, PORT, QAME, QCA, QCNE, R, RB, RSA, S, SEL, SJ, SP, TRIN, TULV, U, UCLA, US, USJ, VEN, and WIS, who provided loans of specimens.

This research was supported by an NSF doctoral dissertation research grant (DEB-9310171), an award from the International Center for Tropical Ecology at UM-St. Louis, and an OTS 92-3 Post-course Fellowship Award. A teaching assistantship from the University of Missouri-St. Louis and an Andrew W. Mellon Foundation Fellowship provided partial financial support for my studies.

I dedicate this work to my parents, Shifen Guo and Zhenxi Zhu, whose enormous sacrifices and unlimited love enable me to devote myself to my pursuit of knowledge. I graciously thank also my brother and sisters who stayed behind to take care of my parents when I departed from my hometown for my academic career.

Gunghua Zhu