In Your Backyard: Lichens

By Bryn Scriver

Susan Will-Wolf, UW-Madison Botany emerita, has composed a guide to the “small and inconspicuous, but oh so cool” Lichens of the Lakeshore Nature Preserve.

The self-guided tour includes a pdf/printable guide and a 10-part video tour on the Friends of the Lakeshore Nature Preserve website. The tour starts at the Picnic Point entrance and guides you along a route guaranteed to show you a variety of lichen species on trees and rocks.

So, what’s so cool about lichens?

Lichens are a symbiosis of a fungus and one or more partners—a green algae and/or a cyanobacterium. The algae or bacteria live inside the fungus and supply it with nutrients through photosynthesis and the fungus gathers water. Because of this symbiosis, lichens can survive in harsh conditions. They are found in most parts of the world in deserts, near mountain peaks, in the steamy tropics, and the frozen Arctic. Lichens cling to surfaces like bare rock, tree trunks, dead wood, and exposed soil. Most lichens are mat-like, flat and crusty looking, but some are leafy or bush-like, and some hang off trees in strands. Lichens come in a range of colors from gray, brown and green to yellow or bright orange. Because they are sensitive to air pollution, dying lichens can also serve as air pollution warning signals.

There are many types of lichens, here are a few.

crustose lichen
Crustose Lichen
foliose lichen
Foliose Lichen
fruticose lichen
Fruticose Lichen
squamulose lichen
Squamulose Lichen