by Ebony Griffin and Roger Bull
While walking through the woods, you are surrounded by lichens. But they are challenging to spot unless you know what to look for. Lichens can be bright splashes of colour on a rock face or a lettuce-like growth on the side of a tree. Some look like tiny red-hatted soldiers standing on the forest floor.
Lichens are present in ecosystems across North America, but they are often overlooked. These organisms are a symbiotic pairing of a fungus and a photosynthetic partner such as an alga or a cyanobacterium. The fungus provides the growth structure, while the photosynthetic partner converts sunlight into food for the pair.
Lichens are the first colonizers of rocks, starting the process of soil formation. They also provide food for many animals, including tundra-roaming caribou. Air-quality-control programs have used pollution-sensitive lichens as an environmental monitoring tool. Humans have also used lichens in dyes and traditional medicines.
With their wide array of growth forms and colours, classifying lichens can be a challenge. This is the task of lichenologists such as the Canadian Museum of Nature’s own Irwin (Ernie) Brodo. Beginning in the mid-1960s, Ernie dedicated his research life to the study of lichens.
In the 1980s, Ernie met Stephen and Sylvia Duran Sharnoff, a pair of Californian photographers who were already fascinated by the beauty of lichens. They became fast friends and decided to join forces to produce a colourful and authoritative lichen guidebook.
The Sharnoffs set off across North America in a camper van to collect images for the book. Drawing on his depth of experience, Ernie wrote the text, including introductory chapters, descriptions, and identification keys for more than one thousand species.
After almost 10 years of effort, they published Lichens of North America in 2001. This impressive 800-page book brings the unique world of lichens to both amateur and professional naturalists.
The new Lichens exhibition at the Canadian Museum of Nature features 16 photos from this book. These images show the diversity of lichen colour and form. With their odd designs and abstract shapes, they could be mistaken for modern art.
Please visit the museum’s Stone Wall Gallery to be surrounded by lichens! We hope these photos inspire you to discover these curious organisms on your next walk through the woods.