Lion Roars

February - March 2009


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Email: lwcapristo@smcm.edu
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NATURE NOTES

The Lowly Life of Lichen

Dead-looking stick covered in lichen

In the second act of Macbeth, Shakespeare’s tragic general says, “Now o’er the one half-world Nature seems dead.” At this time of year, Macbeth’s assertion rings true. Since so many living things are dormant or in hibernation or just plain hiding out, you would think that anything exhibiting life signs would be noticed by us. I say, “Not so.”

Kate Chandler


by Kate Chandler,
Associate Professor of English

“I’ll take the stick with the dead things on it.” Out of the array of natural objects I had brought to class from my winter walks—sticks, stones, shells, seeds—one “American Environmental Literature”
student had selected a four-inch twig of oak that was dotted with lichens.

Early in semesters when I teach this course, I have students adopt one piece of nature to take back to their rooms and write about. I provide no other guidelines; students write what they wish. This student had selected the least dramatic yet the most interesting- looking stick of the bunch, at least to her and to me. No bends, no twists, no nubs, no little limbs sticking out akimbo. It was perfectly straight. Perfectly ordinary. Except for the tiny discolorations scattered across the bark.

“Those ‘dead things?’” I clarified. “They’re alive.”

At a time of year when much of the landscape appears to be dead, our eyes are often drawn to any organic object that exhibits even the least hint of life. Perhaps because lichens do not have horns, claws, or dazzling pink flowers the size of salad plates, they simply do not catch our eye. I would bet that most of us pass lichens with no notice at all. Our attention instead goes to waves crossing the pond, noisy geese passing overhead, or dramatic clouds forming in an otherwise blue sky.

Of course, with such a low profile— literally—this strange plant’s noticeability quotient is at bottom. The lichens on the stick were the dull graybeige of newsprint with an emphasison “dull.” There was no hint of green, to signal life; if anything, a touch of brown tinged their centers. They did look dead. Eye-catching they were not, at least to a public brought up on vibrant Georgia O’Keeffe paintings of poppies and calla lilies.

Prior to class, I had wanted to determine if the lichens were alive and required tending. I checked the oak where I had found the stick and could see that the stick’s lichens were the same as the tree’s. On the tree it was more obvious that they were living; for example, they greened a bit following a rain.

Lichens, it turns out, are remarkably diverse in form. They can be powdery, scaly, gelatinous, hair-like, or in moisture-loaded zones, looped like strands of gossamer necklaces. Unlike crusty lichens that look as if they are painted on rocks and sidewalks—logically called “crustose”—our stick’s growths stuck out from the bark like erratic rows of ears from the most diminutive of miniature mice. These were clearly “foliose,” the second of the three main lichen forms, ones that are shaped like leaves and other foliage. There is another form that I am not sure I have ever seen, the ‘fruticose” type that can branch upward like small shrubs.

In the mid-Atlantic, with no reindeer, moose, or mountain goats to chomp on the lichens and confirm that these particular samples were alive, I had to rely on other observations and a bit of research. (In case you hunger to know, lichens, commonly called caribou moss, provide 90% of caribou winter diet.) Color can be an indicator of life. Lichens can be blotches of yellow, orange, green, gray, black, or the color I had found: tan. The ones called British soldiers protrude upward (well, a quarter of an inch upward) and, given their name, not surprisingly are topped with bright red. So, the fact that ours were newsprint-tan could signal life.

Along the way, I discovered that lichens are not even one plant. They are made up of two organisms: algae and fungi. Algae provide fungi with food, which are able to make use of the sunlight. Without the algae cells living among the tiny threads that make up the fungi, the fungi would die. Without the fungi’s ability to absorb moisture from mist or rain, in this symbiotic relationship, the algae would dry out and expire.

But ours had not dried out; they were still alive.

Checking a patch of lichens each day to witness growth as proof it is alive will not do—don’t slap down your measuring tape to determine its diameter or dig out your beach chair to sit and peer through a magnifying glass expecting activity. As a methodology, this would probably age or enrage you. Lichens grow exceedingly slowly, in some cases 1 millimeter a year but many not as much as .1 millimeter a year.

And don’t try to root one in a jar on your kitchen counter as another test for signs of life. “No one can cultivate a lichen,” pre-eminent botanist Gerould Wilhelm states. “Scientists don’t even know exactly why a certain lichen will appear on a gravestone, for instance. It comes down to an exquisite relationship of minerals, rainfall, wind, sun exposure, and countless other factors that Western science can’t measure.”

Since some lichens have lived for 70 million years, we truly should pay them some attention. Also, since they are a means by which rock is broken into dirt (after some of those millennia), we should grant them at least a bit of our respect.

And, when Shakespeare next laments that “Now o’er the one halfworld, Nature seems dead,” you can walk him right over to the closest boulder or sizeable tree and say “Right you are; nature only ‘seems’ as if it is among the dearly departed.” Then, pointing out a patch of lichen, you can safely claim, “See those dead-looking things? They’re alive.”