ANN ARBOR—Warren H. (Herb) Wagner, University of Michigan professor emeritus of biology and a world authority on the evolution and systematics of ferns, died Jan. 8 at age 80.

A member of the U-M faculty for 40 years when he retired in 1991, “Wagner was widely regarded as the founder of modern day systematics for all groups of plants and animals, and was the first to argue that phylogenetic reconstruction could be made explicit and rational,” said Julian P. Adams, professor and chair of the U-M Department of Biology. “He then proceeded to construct procedures by which this could be accomplished. Today, the phrase ‘Wagner [phylogenetic] tree’ is part of the lingua franca of systematic biologists around the world.

“Herb’s contributions to the plant systematics and evolution have had a profound impact over the years. He was passionate about his research, and maintained an active research laboratory—in which he could be found on all seven days of the week—until a week or two before his death. Herb had an infectious enthusiasm for this field, which he conveyed to many graduate students and co-workers over the years.”

Wagner was born in 1920 in Washington, D.C., and completed an A.B. degree at the University of Pennsylvania in 1942. After Navy service in the Pacific during World War II, Wagner completed his Ph.D. at the University of California, Berkeley; spent one year at Harvard University as a postdoctoral student and an instructor; and came to the U-M as assistant professor of botany in 1951.

His primary research focus was the systematics, hybridization, and evolutionary history of ferns and fernlike plants, but his interests went far beyond ferns, to include oaks and other difficult groups of flowering plants, butterflies and minerals.

He continued to teach following retirement, one of his most popular courses being “Woody Plants” in the School of Natural Resources and Environment. He also taught many courses at the University’s Matthaei Botanical Gardens, which he served as director in 1966-71.

He chaired or co-chaired 45 doctoral committees and served as a member of more than 240 graduate committees

In the 1950s and 60s, working in collaboration with his wife, Florence S. Wagner, he published a series of studies showing that ferns hybridize freely and that hybridization is a major source of new species in plants. That idea is now widely accepted, but 45 years ago it contradicted a dogma that had been imported into botany uncritically from zoology. The Wagners’ research helped botanists realize that the constraints of plants’ habits and habitats and reproductive styles made a different species concept appropriate for them.

U-M botany Prof. William R. Anderson noted that Wagner’s attempts to infer the ancestors of the Hawaiian fern genus Diellia, and his desire to teach undergraduates how to think about evolutionary history, “led him to propose a method of deducing phylogeny that was radical at the time, and with characteristic missionary zeal he went around the country and the world exhorting botanists to abandon their traditionally sloppy approach to the inference of phylogeny and start using methods that are explicit and testable.”

Michael J. Wynne, U-M professor of botany, noted that Wagner “thrived on being in the classroom, but he also loved being in the field hunting for some remote population of plant species or an unusual form of fern. He was a major advocate for the study and appreciation of the role of plants in nature and the cause of conservation here in Michigan and well beyond.”

Edward G. Voss, curator emeritus, Herbarium, and professor emeritus of botany at U-M, noted that Wagner “was an unexcelled lecturer, not just to overflowing classes, but also to countless groups of citizens, clubs and conservation organizations. He attracted innumerable graduate students, who, with their students, went on to become the major cadre of scholars on ferns and related plants in North America.”

Gerald Smith, U-M professor of zoology and of geology and minerals, explained that in addition to being one of the world’s authorities on ferns, “Wagner was an avid collector of rocks and minerals. He was one of Michigan’s leading butterfly experts, with important scientific collections and published papers about geographic variations in Michigan butterflies. For many decades, he was our most positive and enthusiastic source of guidance to students.”

Wagner’s many honors included election to the National Academy of Sciences in 1985 and the Asa Gray Award from the American Society of Plant Taxonomists in 1990, and he served as president of seven professional societies. He also was honored by the University with the Distinguished Faculty Achievement Award and the AMOCO Foundation Good Teaching Award.

He is survived by his wife, Florence, their children, Margaret and Warren, both of Ann Arbor, and two grandsons.

A memorial service will be announced at a later date.