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New scientific guide to North American lichens penned by Museum scientist

Colin Freebury © Canadian Museum of Nature.


Dr Irwin Brodo is his lab at the museum's research facility, located in Gatineau, Quebec.

Dr. Irwin Brodo is a world authority on lichens. The researcher emeritus at the Canadian Museum of Nature has now created a landmark reference that provides the scientific “signposts” to identify more than 2,000 lichens found in North America.   

Keys to the Lichens of North America is published by Yale University Press. It’s a complement to Brodo’s award-winning 2001 book Lichens of North America, which he authored with photographers Stephen and Sylvia Duran Sharnoff. This weighty tome features written descriptions of about 800 lichens, and references to about 700 more. Hundreds of striking photos reveal the wide range of colour and form of these fascinating organisms.  

The new manual identifies lichen species through the use of “keys”—critical tools for biologists in the process of species discovery. ʺKeys provide the fastest way of getting to a scientific name, because they present the user with a series of choices,ʺ explains Brodo. ʺAll the user needs to do is look at the specimen in question, decide which choice to take, and then follow those choices to get the name.ʺ Once the species name is pinned down, any number of questions can be tackled—including issues related to conservation, ecological monitoring or studies of biodiversity.

© Canadian Museum of Nature


Brodo, who officially retired from the museum in 2000, saw a need for Keys to the Lichens of North America while teaching a summer course on lichens at the Eagle Hill Institute in Steuben, Maine. ʺEvery year I updated the keys, and I found there were always species to be added, mistakes to be corrected, and old keys to be rewritten,ʺ he explains. New species and genera were also being identified using DNA analysis, resulting in new classifications and names.

His new publication provides keys for the most common or conspicuous lichens found in North America—2,045 species in all, about 40% of the known species on the continent. “It’s a good hunk of the lichen flora, including most lichens that people would encounter,” he says.

Keys to the Lichens of North America is geared to students, professional biologists, serious amateurs, or anyone with a need to identify lichens in the classroom, lab or workshop. A comprehensive bibliography is included, as well as colour photos by the Sharnoffs and line drawings by Ottawa artist Susan Laurie-Bourque to illustrate the detailed glossary.  

So what’s next for the devoted lichenologist? Brodo fully expects other researchers will add to his manual over time. With that in mind, the book includes space for users to add their own notes as they use the reference for lichen identification.   

But he also has his mind set on completing a flora for the lichens of Canada’s Haida Gwaii (Queen Charlotte Islands)—a region where he first collected in the 1960s, with an estimated 600 lichen species! Until then, Brodo will continue to be found studying his favourite organisms in the museum’s national research and collections facility in Gatineau, Quebec. 

About Lichens:
Lichens are found on every continent and can grow in frigid polar regions, harsh deserts, as well as your backyard! A lichen is part fungus and part green alga or a cyanobacterium (sometimes both). Lichens play important roles in ecosystems: they are among the first colonizers of bare rock, they provide food for animals and they can serve as air-pollution monitors. Lichens are also used in dyes and traditional medicine.