Sunday, April 25, 2010
Lookin' for Lichens
Mycologist Sue Van Hook teaches a pine-needle lesson to one of the participants in a Lichen Hunt she led in Wilton on Saturday.
Well, there's an awful lot to learn about lichens. I confess I retained just a small bit of what mycologist Sue Van Hook had to teach us about them on the walk she led yesterday at Wilton Wildlife Preserve, but here are a few of the basics:
1. A lichen is an organism composed of a fungus and an alga in a symbiotic relationship, although sometimes cyanobacteria contribute to the mix.
2. Lichens can be divided into three different growth forms: Crustose (which look like they are painted on), Foliose (which look like leafy growths divided by lobes), and Fruticose (which are bushy or shrubby, some containing distinct stalks).
3. Lichens can be found on three different substrates: on the ground, on rocks, and on trees.
The rest of what's known about lichens would fill a big library, but the basic knowledge I came away with was this: Lichens are everywhere, but most of the time we don't see them because many are very, very small. Luckily, Sue brought along a whole bagful of magnifiers so we all could take a close look. (See that dark maroon patch right in the center of the trunk between those two hands? I got all excited, thinking I'd found an unusual lichen, but when I looked through the magnifier, I found liverwort instead. Liverworts are really neat, too!)
We must have made quite a sight, hunkered down to peer closely at all the marvelous detail we would miss with our naked eyes. But just like the happy children that joined our group, we soon forgot any inhibitions because we were so enthralled.
We didn't examine any crustose lichens (the kind that paint boulders with pinks and grays and greens), but we did find lots of the other two kinds, the foliose and the fruticose.
Here are two kinds of the foliose type, growing on a tree trunk. I believe the green one is a Green Shield Lichen, an extremely common species, but I didn't get the name of the gray-colored one.
Here's a tree limb with lichens both foliose (the orangey one) and fruticose (the bushy one) crowding against one another. And looking closely, I think I see some kind of black furry stuff in the mix. Another lichen?
Speaking of black lichens, here's one that I think Sue called Tree Jelly, and it's remarkable for more than its color. Apparently, almost all lichens this dark have cyanobacteria in their mix.
And now for another lichen notable for its color: British Soldiers, a fruticose form that bears bright red fruiting bodies atop its branching stalks.
This next one's a close relative of those British Soldiers (they're both of the Cladonia species), only note that the fruits are borne atop single, rather than branching, stalks. This has a wonderful name: Lipstick Powderhorn.
Here's another Cladonia family member, and I think it's called Trumpet lichen. There's a similar cup-shaped lichen called Pixie Cups, but that one has bright red dots around the cup's rim. The cup shape of these lichens promotes reproduction, for as rainwater splashes into the cup, spores released by those fruiting bodies are forcefully ejected, possibly to land where a new lichen body can grow.
We didn't find this foliose lichen yesterday (I found it last December up in the mountains at Moreau), but I think it's so pretty I wanted to see it again. It's called Orange Rock Posy. Don't you just love that name? It looks like two different kinds, doesn't it, but the green bubbly stuff underneath is the leafy part (called the Thallus) while the orange discs are the spore-producing bodies (called Apothecia).
Reading back over what I wrote here, I sound pretty ignorant, don't I? It's all "I think . . .", "I believe . . .", "I don't know . . ." Well, the truth is, I'll bet even Sue didn't know the name of every lichen we found. With hundreds of genera and up to 20,000 species to keep track of --many of which can be distinguished only by microscopic examination -- there aren't many people who know every one at first sight. The field guide I own (Lichens of the North Woods by Joe Walewski) includes just 111 northern lichens. But it also contains lots of good information about lichens generally, as well as a very clear lesson on lichen biology. Plus, the color photos are clear, and the whole book fits in a pocket. As for me, I don't need to know the name of every lichen I find (although that would be nice). The point is to keep on looking. And for sure, I'll keep on finding them, because lichens are everywhere!