Not far from the tree with the beetle engravings I discovered one with a tiny poof of lichen. Just the one, on a small tree that could even have been a long-dead sapling; there were no others near it, or even in the immediate area, that I could spot. I found this curious. At first I thought it was perhaps a reindeer lichen that had been picked up and dropped there by some animal, but when I picked it up it seemed to have grown around the twig, with a distinct groove down the centre. I ran off several shots, but lichens are a tough bunch to decipher, and I didn’t really know for sure what I was looking at.
I carried on up the trail, and a short distance later came upon some thick fruit-bearing trees, perhaps crabapples. I’d walked by these trees dozens of times before, and never noticed anything remarkable. But for whatever reason, that day something caught my eye: fuzzy patches of green lichen growing from their trunks. Whereas there’d just been the one on that first little tree, here there were dozens. None of them were very big, even the largest was not much larger than a tennis ball. Most were only half that size. They were very delicate and fine, almost hairlike. I had more of a suspicion as to the identity of these, but it would require returning home to ask the internet (my god is named Google; Google will provide).
I am fairly certain that these are Usnea sp., also known as Old Man’s Beard (which may refer to one of many species of Usnea lichen), or at the very least the latter bunch on the crabapples are. I’m not completely sure about the first one, I would probably need to go back to check out additional characteristics. Usnea lichens typically grow from the branches or trunks of trees, and are always fruticose – that is, highly branching. Some species grow more thickly than others, and some have broad flat bits that remind me a bit of opened venus fly trap jaws. There are a number of species that grow in Ontario, but I think this one might be Usnea subfloridana, a particularly filamentous species but one that doesn’t typically grow very large or long. Some species can grow very long, a foot or more, and completely cloak the branches of a tree.
All lichens are susceptible to air pollution, but Usnea lichens are especially so. They’re one of the first types of lichen to disappear with air pollution. Even when they persist, they may not grow more than a few millimeters. Their presence here is likely an indication of reasonably clear air quality.
When I think of Usnea, I typically think of Northern Parula warblers. Parulas are almost entirely dependent on long, draping species of Usnea for their nests. They don’t just use the lichen in the nest, the lichen is the nest. They’ll find a nice thick clump of the stuff and hollow out the inside. They don’t even always line it. Because the sort of Usnea the parula prefers mostly occurs in the coniferous forests of the Canadian Sheild, the bird is rare in southern Ontario. We’re right at the edge of the Shield here, but I don’t think these little puffs are going to cut it.
Most Usnea lichens, along with a few others such as reindeer lichen, contain usnic acid, a bitter-tasting molecule believed to be used to deter animals that might browse on the lichen (apparently it doesn’t deter the reindeer). It also happens to be a very potent antibiotic and antifungal agent, and is high in vitamin C. These latter properties resulted in it being a common medicinal agent used by Native Americans to treat infections – both internally, as a tea, and externally, as a compress on wounds. The fine, branching nature of the lichen also made it a good substitute for gauze. In modern day herbal medicine it is often used in teas or other products intended to treat respiratory and urinary tract infections.
All good things to know if I find myself lost and sick in the northern woods…