Charlie Werth left us much too early, and with many of his ideas, insights, and projects to be explored. This symposium honors Charlie's memory and builds on his passionate devotion to the biology of ferns. Charlie was always one of those at the cutting edge of research on the population biology and evolution of ferns. He pioneered techniques to study fern genetics and proposed creative hypotheses about how the unique genetic attributes of ferns constrained and contributed to their distinctive evolutionary processes. Charlie was fascinated by some of the most challenging and dynamic groups of ferns, and he made significant progress in understanding how and why they were so difficult to classify. One of Charlie's major advances was interpreting the polyploid nature of ferns, and because of this, Doug and Pam Soltis agreed to provide new perspectives on this important phenomenon. Building on this polyploid theme, Don Farrar and Mary Stensvold will report on allopolyploid speciation in Botrychium. The remaining presentations all focus on groups that Charlie studied. Charlie considered reticulate evolution in Asplenium for his dissertation research and Johannes Vogel, Harald Schneider, and their colleagues will present updates on this world-wide genus. Charlie also studied Dryopteris and one of his fascinations was with the "semicristata" genome. Diana Stein and associates will bring us a synthesis of that research. Charlie contributed to our understanding of population dynamics in ferns and William Speer and co-workers will consider perhaps the most dynamic fern, Pteridium. Finally, Charlie's last research adventures looked at the process of speciation in Athyrium and Jakob Schneller will provide new information on this complex group. Thus, the symposium will touch on approaches, ideas, and systematic advances in the pteridophytes. Charlie would certainly enjoy this opportunity to dialog about and synthesize information on populations, species, and evolutionary processes.

Key words: allopolyploid speciation, fern biology, polyploidy, reticulate evolution, semicristata genome, Werth Charles R.