Lichens

Unfortunately there are people who think that once the leaves have fallen there is nothing left to see outside until spring, but they couldn’t be more wrong. Lichens for instance, are there year round and unless you live in a place with poor air quality they are everywhere; on trees, on stones, on the ground, and even on buildings, roofs, windows, and sidewalks. They are like small jewels that have been sprinkled throughout nature and one of my favorites is the smoky eye boulder lichen (Porpidia albocaerulescens) shown above. The blue dots are called apothecia and are where its spores are produced. They are blue because of the way the light reflects off the thin wax coating that they are covered by. In this case the body of the lichen, called the thallus, is a brownish gold color. The thallus can also be gray and the apothecia gray to black. One of the things that can make lichen identification difficult is the ability of some lichens to change color in different light, and this is one that does. It can look very different just a few feet away.

The apothecia on this star rosette lichen (Physcia stellaris), is a good example of how colors can change, even on the same lichen. This lichen has dark brown apothecia that are often pruinose. Pruinose refers to the white, waxy, powdery coating like that found on the smoky eye boulder lichen in the previous photo. You’ve no doubt seen examples of this waxy “bloom” on blueberries and plums. I’ve noticed by watching lichens that have pruinose apothecia that the coating can reflect light in different ways, sometimes appearing gray and at other times more blue, and sometimes even black. The apothecia on this lichen show a range of colors, from brown to light blue. The way the sunlight strikes it has a lot to do with its colors.

I used my magic gravity defying penny so we could get an even better idea of the scale of some of these lichens. For those of you not familiar with the size of a penny, they are 3/4 of an inch (19.05mm) in diameter. The powdery sunburst lichen just above it is almost the same size. The lichens below, right and left of the penny are star rosette lichens like the one we just saw in the previous photo. That penny could use a good cleaning.

This is the powdery sunburst lichen (Xanthomendoza ulophyllodes) we saw above the dirty penny in the previous photo. This foliose lichen is easy to see even when it’s small, because of its bright orange yellow color. This lichen really likes moisture and is often found growing near channels that carry water on stone or bark. A foliose lichen has a lobed, leafy look.

British soldier lichens (Cladonia cristatella) like to grow on damp wood like rotted stumps and logs, but I’ve found them on buildings, fence posts, and built up forest litter on boulders. At this time of year I don’t pass too many mossy old tree stumps without having a glance for British soldiers. Their bright red apothecia make them easy to see, even if you’re colorblind.

Pink earth lichen (Dibaeis baeomyces) closely resembles bubblegum lichen (Icmadophila ericetorum.) One of the differences between the two is the length of the stalks that the plump pink apothecia sit on. They are longer on bubblegum lichens than they are on pink earth lichens. Both are very beautiful things that are rarely seen in this area. The whitish thallus, or body of the lichen, grows on soil; usually on dry acidic soil near blueberry and sweet fern plants. It can sometimes have a bluish cast as well.

I find pebbled pixie cup lichens ((Cladonia pyxidata)) growing on soil or rotting stumps and logs, and occasionally on stone. Pixie cups look like tiny golf tees or trumpets. They are squamulose lichens, and the golf tee shapes arise from leafy growths called squamules. A squamule is a lobe of the body of the lichen (thallus,) and  squamulose lichens have small, leafy lobes.

Though pixie cup lichens are squamulose they have fruticose fruiting structures called podetia. The parts that look like tiny golf tees are called podetia. “Podetia” describes a stalk like growth which bears the apothecia, or fruiting bodies. This example shows some almost microscopic dots around the rim, which are its apothecia. Finally, frucitose means a lichen has a bushy, vertical growth. Since this example has squamules even growing inside the tiny cups it must be a pebbled pixie cup lichen.

A single raindrop was caught in the cup of this pixie cup and it illustrates how the cups are meant to do exactly this; they are splash cups and when a raindrop lands in them the water splashes the spores out and away from the lichen to hopefully colonize new ground. Pixie Cups and other Cladonia species like reindeer lichen contain didymic acid, and they were once used by herbalists to treat tuberculosis.

Dog lichens will grow on soil, rotting wood, or stone as this one was. The example pictured is I believe, a membranous dog lichen (Peltigera membranacea.) Dog lichens are associated with mossy areas because the mosses provide the moisture that they need. It is known as membranous lichen because it is thin and pliable. It is also a foliose lichen because it is lobed, or leaf like. The upper part of the body (Thallus) is undulating or veined. This lichen is large and easy to see. It is also probably quite old.

One theory behind the name “dog lichen” says that the name refers to the large, lobed body of the lichen looking like dog ears. It sounds plausible, but so do the other three theories I’ve heard. One says the fang like rhizines look like dog’s teeth, another says the entire lichen body looks like a dog, and yet another says that the apothecia, or fruiting bodies, look like dog ears. I’ve never seen this one produce fruiting bodies so I can’t verify that last one and it doesn’t really look like a dog to me, so I can’t verify the second one either.

What sounds most plausible to me about the origin of the name “dog lichen” are the white “roots” on the white underside of the lichen body. They are fang like and called rhizines. On some lichens they can be quite bushy, but on Peltigera membranacea they are narrow and thin. They are one of the identifying characteristics of this lichen along with its thin, flexible, undulating thallus.

Common goldspeck lichens (Candelariella vitellina) are uncommonly beautiful. Look for this bright yellow crustose lichen on stone. It’s a very artistic lichen and I like the patterns that it makes. I see it on gravestones quite often.

It shouldn’t come as a great surprise that, at high magnification, the body of the common goldspeck lichen looks like it’s made up of tiny golden specks. The book Lichens of North America describe the body of this lichen as “little cushions of flattened granules.” This lichen is sometimes sterile, with no fruiting bodies present, as this one appeared to be.

Scattered rock posy lichen (Rhizoplaca subdiscrepans) is both beautiful and unusual with its brain like body and orange fruiting bodies. This one was growing on stone in full sun. There was a time when I knew of only one example but now I see them everywhere, even on mountain tops. This example was about as big as a penny.

If you spend time walking along old stone walls eventually you’ll see a stone with a splash of bright orange on it and it will probably be the sidewalk firedot lichen (Caloplaca feracissima,) so called because it is a lime lover and grows on concrete sidewalks, which have lime in them. When you see it in a stone wall it’s a fair bet that the stone it grows on has limestone in it too. This stone is almost completely covered by it.

A closer look at this example of the sidewalk firedot lichen showed it was made up of mostly irregularly shaped fruiting bodies, so it was making plenty of spores. It was raining at the time so it was also very wet. Lichens are at their best when they are wet because that’s when they’ll show their true colors and size, so that’s when serious lichen hunters look for them. A misty or drizzly day is perfect.

One thing you learn quickly when you decide to study lichens is that your pockets will be as full of unknowns as they are knowns, and this lichen shows why. You’ll see why in the next photo, so try to remember how it looks here.

Not only do lichens change color but shape as well. It’s hard to believe that this is the same kind of lichen that we saw in the previous photo but it is, and it is the apothecia in full “bloom” that makes it look so different from photo to photo. This is why it has taken me as long as three years to identify some lichens. I’m not completely comfortable with my identification of this one but I think it might be the brown eyed rim lichen (Lecanora epibyron.) Brown eyed rim lichen is described as a “white to very pale brown crustose lichen with many red-brown apothecia with a white margin.” It seems to fit, but if you know this lichen and know that my identification is wrong I hope you’ll let me know.  I found it growing on ash tree bark.

As its name implies maple dust lichen (Lecanora thysanophora) grows on the bark of maple trees, but I’ve also seen it on beech, oak, and basswood. One of the easiest ways to identify this lichen is to look for the white fringe around its perimeter. This is one of those lichens that I never saw until I stumbled across it one day, and now I see it everywhere. This beautiful example was about 3/4 of an inch in diameter, or about the size of a penny.

Some lichens are very easy to identify because there aren’t many others that look like them, and the toadskin lichen is one of those. Toadskin lichens are another one that shows color changes. When wet it is pliable and pea green and when dry it becomes crisp and ash gray. This example hadn’t completely dried out but it was well on its way. Toadskin lichens get their common name from their many “warts.” They attach themselves to stone at a single point that looks like a belly button, and that makes them an umbilicate lichen. This toadskin is very special, because it is the only one I’ve ever seen that wasn’t on a hill or mountain top. It grows on a boulder at the very water’s edge of a lake and now I know, if the day comes when I can no longer climb, I’ll still be able to see these beautiful little things.

I hope you’ve enjoyed seeing a few of the lichens I know and I hope you’ll look for them in your area. Just look closely anywhere you happen to be; they’ll be there too.

Oh what a strange nature is knowledge! It clings to the mind when it has once seized on it like a lichen on a rock. ~Mary Shelly

Thanks for coming by.