As members of the Ottawa Field Naturlists' Club (the oldest natural history club in Canada), the ADG and I recently attended a lichen workshop led by renowned, local lichenologist Irwin Brodo. He gave a brief presentation on lichen basics, including a definition of just what the heck lichens are.
"The most significant thing about all lichens is that they are two plants, not one. Each lichen plant body or 'thallus' is a biological twosome composed of a fungus living in intimate contact with an alga. The relationship involves much more than the mere contact or even relative position of the constituents; it results in the formation of the entirely new, self-sufficient, functioning unit which gathers raw materials, manufactures food, conducts an exchange of of vitamins and growth substances, and often even reproduces as if it were a single plant." Cooool!
It was a great way to spend a late-winter Sunday and I'm really glad to have had the opportunity to learn a little more about lichens. I will definitely look more closely at these amazing organisms. Next, I want to learn about which lichens are edible!
Here are just a few common, urban tree lichens you can find in the Ottawa area: