Northern Illinois reveals itself as 'land of lichen'

When the wintry world outside is gray and you crave a little color, put a little lichen in your life.

Lichens are colorful organisms, like the splotch of orange on the tree trunk in your yard, or the blue-green coating on the rock at the end of the driveway. They're ubiquitous and unobtrusively beautiful in the blah-ness of winter.

Lichens are one of nature's bizarre experiments that worked. They're usually lumped with plants in biology books, but they're not exactly plants.

A lichen is best described as an alliance of life forms.

One key player is from the group known as the Kingdom Fungi. The other partners include representatives from the Kingdom Monera, the algae, and the Kingdom Protista, the cyanobacteria.

It's as if ambassadors from the three kingdoms had a summit and decided to strike a deal. Together, maybe they could do what none of them could do separately.

Like, be lichen.

What you see growing on the rock in your garden is a life form made up of several organisms in a cooperative arrangement. Biologists call this symbiosis. It's actually a classic case of co-dependence. As a team, they are a living entity; apart, they cannot survive. The fungal partner cannot make its own food and thus depends on the algal partner for photosynthesis; the alga, in turn, depends on the fungus for form and structure and stability.

This living arrangement is actually pretty cool. They are friends with benefits, and the symbiotic deal they've struck allows lichens to exploit a wide range of habitats. They thrive in the frozen tundra and in hardwood forests. You can find them in swamps and in cemeteries. They inhabit deserts and prairies and, of course, your backyard. Lichens are hardy and they don't ask for much, just a substrate (something to grow on), a little sunlight, some moisture once in a while -- and clean air.

So, you may be asking, how will I know a lichen when I see one?

Lichens come in all shapes and colors, and they grow in all kinds of places. It's easier, therefore, to explain what lichens are not. They are not wildflowers, which boast pretty petals and produce seeds. They are not mosses, although they may grow in similar environments. They are not mushrooms, even though they have a fungal component.

In general, you can spot a lichen by its form, structure, and location.

If you see something that from afar looks like yellow paint on a branch, or a bluish-gray coating on a rock, lime green spots on a fence post, or a black blob on a boulder -- you've got lichen.

Now check out the shape and form. (To do this, your best bet is to use a hand lens or magnifier.) The lichen may be flattened and leaf-like, hugging a twig or a branch. It might be crust-like and appear to be plastered to a rock or bark. (If you try to remove this kind, you'll end up taking the rock or bark as well.)

A lichen might also be branched like a miniature shrub, and attached to the substrate by a miniature suction cup.

What do lichens do, anyway? They grow, very slowly.

Lichens grow so slowly that you'd have to wait for centuries to see them gain a few inches. Not only do they grow slowly, they get old. Lichens are among the oldest organisms on earth. Scientists analyze ancient lichens to track changes over time, such as glacial activity and climate change.

Lichens also reproduce. But lichen dating and mating is somewhat complicated. The quick and easy way to make more lichen is to reproduce vegetatively -- in other words, without the hassle of a partner.

Lichens often do this by making special packets of algae and fungus that, when carried by wind or water or critters, can -- voila! -- generate new lichen.

Sometimes, though, lichens reproduce sexually -- just to mix things up, genetically speaking. Sexual fusion of fungal cell nuclei takes place in fruiting bodies called apothecia, resulting in spores. The spores are disseminated hither and yon; if lucky, one will land in a good spot. The spore germinates into a fungus. The trick is that the newly germinated fungus needs to snare an alga or it will perish. A fortuitous union may occur, or the fungus may "steal" an alga from another lichen.

Well, OK, but what do lichens do for us? (It is all about us, isn't it?)

Perhaps the most often-cited use of lichens is in air-quality monitoring. Lichens readily absorb water and air from their environment -- and all the chemicals, good or bad, that come with them. Some species are highly intolerant of air pollution and their populations diminish as air quality declines. Due to their sensitivity, lichens are the canaries in the coal mine to warn us when things are getting bad.

Scientists need numbers, and lichens provide good data. They are simple, inexpensive, and reliable measures of environmental quality used by scientists all over the world.

Laboratory analysis aside, lichens have a fascinating array of other uses. Some species are edible for both people and wildlife.

According to Irwin Brodo and Sylvia and Stephen Sharnoff in their magnificent tome "Lichens of North America," horsehair lichen is a traditional food source for Indians of the Pacific Northwest.

Medicinally, lichens hold tremendous potential. The lichen known as rock tripe is being studied as a growth inhibitor of HIV, the virus leading to AIDS. Usnic acid from the lichen Usnea is extracted for its antibiotic properties. Some lichens have cathartic effects, both as laxatives and expectorants. Some are some are used as tonics and poultices. Medical research has barely scratched the surface of the biochemical benefits of lichens.

Lichens are entwined in cultural history and art, too. Weavers search far and wide for lichen to dye their fabrics. Colors extracted from lichen are used in art and ceremonial body painting. And what would the wig-wearing public of 16th- and 17th-century Europe have done without lichen dust on their powdered wigs? Lichen is still used in India today for hair cleansing and fragrance.

Lichens are just plain cool. And pretty.

According to local lichen expert Rich Hyerczyk, over 400 species of lichens have been collected in Illinois, fully half of which inhabit northern Illinois -- which leads me to believe we should add "Land of Lichen" to our license plates.

They're out there. Go find them.

Keep your eyes open, carry a hand lens, and feast on the beauty of these awesome organisms.

Did you know?

• Nineteenth-century British author Beatrix Potter of "Peter Rabbit fame" was a pioneer in lichenology. Thinking outside the Victorian box, Potter dared to enter the traditionally male field of science. "She was the first person in Britain to speculate in a scientific paper that lichens are symbiotic life forms, conducted experiments in her kitchen, and recorded in detail her observations of algal and fungal properties." http://www.bpotter.com

• Scandinavians used wolf lichen to poison wolves. They mixed the lichen with reindeer blood, meat, and ground glass. Any wolf nibbling on this concoction would be a goner in no time. Fortunately, the practice never caught on in North America.

• Swedes used lichen in distilling brandy until they exhausted the lichen supply in the late 1800s. In Siberia, lichen was used as a flavoring for beer.