JOHN W. THOMSON JR.

PROFESSOR EMERITUS

- Lichens of Wisconsin by John Thomson is now published and available, order it here.

John Thomson has published on American lichens for 63 years, monographs and synopses of major lichen genera in North America and numerous floristic studies. Most important of all, he has become the world's most knowledgeable Arctic lichenologist. His productive scientific life was not carried out in a museum, where research was the only professional expectation, but in teaching institutions, where non-teaching duties were also numerous and diverse. In spite of these impositions and myriad requests for help from young lichenologists (to whom he never said no), he doggedly pursued his love of the lichens and even in retirement pursues it still.

For younger lichenologists today, it is hard to imagine what our field in this country was like in first part of this century, the America of Thomson's youth. Travel in this immense land was slow, difficult, and expensive. The few botanists interested in lichens rarely saw each other, and none had had an opportunity to study in Europe. Those were years of great isolation. Thomson's interest in lichens began then, in the mid-1930s, and his first paper was published in 1934, when he was 21, a list of species collected on a field trip of the Torrey Botanical Club to a swamp in New Jersey. A few years later the world was plunged into war, and it would be 1945 before peace was to return. By then, Thomson was in Wisconsin where he would remain permanently, eventually joining the faculty of the University of Wisconsin at Madison.

Just prior to the outbreak of World War II, in 1939, the Swedish lichenologist Gunnar Degelius came to the United States to collect. His resultant papers, one on Maine (1940) and the other on the Great Smoky Mountains (1941), showed American lichenologists how a precise understanding of the European lichen flora would reveal that many American lichens that they previously called by European names were, in fact, different and native or endemic American species. By then Thomson had set himself two goals: first, to catalog the North American lichen flora as precisely as possible, a floristic goal; and, second, to examine major North American genera critically, a monographic or synoptic goal. He would spend the rest of his career working toward these objectives.

Early on he produced treatments of Cladonia and Peltigera, first for Wisconsin (1942 and 1946) and in 1950, Peltigera for all of North America. He also wrote on Physcia (1963) in the broad sense, before it was divided into the smaller genera known today. He next returned to the genus Cladonia, a book-length synoptic summary (1967), bringing together his own original work on that genus and the monumental, scattered, but never-summarized research of Alexander W. Evans (d. 1959). (It was Evans who, after the War, championed Yasuhiko Asahina's microchemical techniques at a time when the chemical aspects of lichenology were scorned and dismissed in Europe.) This book also brought together the work of a small but sharp-eyed group of American Cladoniologists, including L.W. Mriddle (d. 1921), C.K. Merrill (d. 1927), and C.A. Robbins (d. 1930).

Thomson's intense interest in floristics comes from his love of field work. He is a vigorous and critical collector, adding many new species and records to the American flora. In the early 1950s, he started a long series of collecting trips to various regions of the American Arctic, regularly generating reports of his finds. He later summarized part of his work in the book Lichens of the Alaskan Arctic Slope (1979) and subsequently wrote the 500-page American Arctic Lichens: 1. 7he Macrolichens (1984). The second volume, treating the American Arctic microlichens, just off the press, brings the number of lichen species covered close to a thousand. And always true to his interest in floristics, he is currently at work on a flora of the lichens of his adopted state, Wisconsin, a genuine labor of love.

In retirement, John lives in the same farmhouse with his beloved wife Olive, a botanist of flowering plants, is always with him. John and Olive raised their children in this home and cultivated their garden and tended their livestock on this farm in that beautiful region of America where the deciduous forest merges into the Great Plains. Although he was born 85 years ago in Scotland, John Thomson is a quintessentially American scientist, the Dean of American Lichenology.

Degelius, G. 1940. Contributions to the lichen flora of North America. I. Lichens from Maine.
    Arkiv  för Botanik 30A: 1-62.
Degelius, G. 1941. Contributions to the lichen flora of North America. II. The Lichen
    flora of the Great Smoky Mountains. Arkiv för Botanik 30A(3): 1-80.
Thomson, J. W. 1934. Field trip of Dec. 10. Torreya 34(l): 21-22.
Thomson, J. W. 1942. 7he Lichen gunus Cladonia in Wisconsin. Amer. MidL Nat. 27:
    96-709.
Thomson, J. W. 1946. The Wisconsin species of Peltigera. Papers on Wisconsin lichens No. 2:
     Wis.Acad. Sci., Arts and Let. 38: 249-271.
Thomson, J. W. 1950. The Species of Peltigera of North America north of Mexico. American
    Midland Naturalist 44: 1-68.
Thomson, J. W. 1963. The Lichen genus Physcia in North America. Nova Hedw. 7: 1-172.
Thomson, J. W. 1967. 7he Lichen genus Cladonia in North America. University of Toronto
    Press, Toronto, 172 pp.
Thomson, J. W. 1979. Lichens of the Alaskan Arctic Slope. University of Toronto Press,
    Toronto, 314 pp.
Thomson, J. W. 1984. American Arctic Lichens 1. The Macrolichens. Columbia University
    Press, New York, 504 pp.
Thomson, J. W. 1998. American Arctic Lichens 2. The Microlichens. University of Wisconsin
    Press, Madison, WI. 736 pp.