When I began learning about nature, it was trees and wildflowers that captured my attention. Trees were majestic, providing homes for many species of wildlife. Wildflowers seemed like artwork scattered through the woodlands. Then I realized how interesting shrubs are, and what about those gorgeous ferns? The learning curve seemed endless, as well as fascinating.
Lichens were way down on my list, until I started associating them with wildlife. Then I started paying more attention to these interesting organisms.
Lichens are certainly oddities, being neither plant nor animal. They are composites, made up of a fungus (which cannot photosynthesize) and one or more organisms that are able to photosynthesize, such as algae or certain types of bacteria. Having no chlorophyll, fungi cannot photosynthesize. Algae and cyanobacteria, photosynthesize quite well.
This partnership—seemingly a truly symbiotic relationship where both partners benefit—results in something completely different, containing properties of each. Some biologists have theorized that the fungi have actually captured the algae or cyanobacteria, in a way forcing it to photosynthesize for them. Around lichens, there seems to be more theories than answers. In any case, the partnership can survive a far wider range of environmental conditions than the individuals alone.
In any identification, it is best to start with some distinct species and then expand your knowledge base. It is also useful to group things together. There are three categories of lichens—foliose, fruticose, and crustose. Foliose lichens are leafy and generally large, with a distinct upper and lower surface. Fruticose lichens are often rounded in cross-section, with no distinct upper or lower surface. Crustose lichens are crusty, and are closely attached to the rock, bark, or whatever they are growing on.
Three lichens captured my attention early and remain my favourites. Old Man’s Beard—a fruticose lichen—is the long, stringy, pale green lichen that you find mainly growing on spruce trees. We always fashioned them into “beards” when schools came out to Macphail Woods. But it was its usage as nesting sites by Northern Parula Warblers that got me hooked. I was looking for the nesting site of a pair of these warblers when I saw the female climb into a hanging clump of Old Man’s Beard and proceed to shape the clump into her nest.
Another that I come across quite often is the foliose Lung Lichen. There are several varieties native to PEI. It is quite common on Red Maple trees, looking leafy and green. The name Lung Lichen comes from the Greek tradition of associating the medicinal uses of an organism with the part of the body it resembles. I don’t believe that Lung Lichen was actually a cure for any lung-related problems, but the name persists.
The third common lichen that I find very interesting is another one that is easy to find and has a very descriptive name. British Soldier Lichen can be found growing across the province, in a wide variety of habitats—anything from old fenceposts and wooden shingles to dead wood and rocks. It is another fruticose lichen, usually pale grey with red “hats”, hence the reference to British soldiers.
Because lichens tend to be dry and sterile, they can be found in the nests of many birds. The Ruby-throated Hummingbird makes its nest out of spiderwebs and tube lichens—small, grey lichens that are very common across the province.
Lichens are critical parts of our ecology. Just because we don’t notice them much, it doesn’t mean that they aren’t deserving of our attention.