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Look for Lichens on Your Next Winter Walk

Even in the colder months it is fun to get outside and explore the world around you. There are birds visiting just for winter, mammals that grow winter coats and stay active and trees that stay evergreen. There is also a unique species that is everywhere but often overlooked: lichen.

Different kinds of lichens growing on a tree branch.
Different kinds of lichens growing on a tree branch. (Photo via Shutterstock)

Be curious about the amazing natural world around you. Get outside and go on a lichen hunt!

What is it?

Lichen can be found growing on tree trunks, fallen twigs, rocks and even park benches or fences. In our local habitats, species of lichen can be found in pretty shades of green, orange or yellow. Globally, lichen comes in many different colors.

Sometimes lichen can be confused with moss. Moss and lichen share some similar features, including where they can grow. But moss is a type of plant growing like a soft, natural carpeting. Lichen is not a plant and, around us, it grows more like a crust or little, flat, lobed structures. So lichen is not a plant, but what exactly is it?

Two in one

(Illustration via Shutterstock)

In the illustration above, the tan color that dominates the picture is the fungal part of lichen. The green represents both the algae and cyanobacteria. This picture shows the lichen shooting out spores that can grow into new lichen.

It can be hard to explain what lichen is because it is actually two or sometimes three separate things living together as one. Lichens consist of fungus, algae and sometimes cyanobacteria. (Cyanobacteria — sometimes called blue-green algae — is a photosynthetic microscopic bacteria. There are 2,000 known species.) Each of these alone are separate groups of living things with many species, but when together, they become a complex lifeform called lichen.

The fungus makes up most of this partnership. Imagine a sandwich where the two slices of bread are connected to each other through many bread threads. The fungus provides the home by attaching to the surface of something. The algae and sometimes cyanobacteria, both of which normally can only survive in water, are contained inside these little bread threads. They make food for the lichen through photosynthesis, just like the leaves of a plant.

A pioneer

(Illustration via Shutterstock)

Pioneer means being the first. It could be the first person to explore an area or the first person to discover or study a new type of science or art. In the natural world, a pioneer is the first species to colonize a lifeless location.

A lichen has root-like structures, but they just help lichen attach to different surfaces. They are not roots absorbing minerals, nutrients and water from the soil.

Lichen absorbs water straight out of the air, and the algae and cyanobacteria parts use sunlight to make food. Needing only air and sunlight is what allows lichen to grow almost anywhere on almost anything. As lichens die and decompose, the organic matter they leave behind creates soil. Very slowly over a long, long time, this process makes enough nutrient-rich soil to welcome more species to grow and live in the environment.

Get ready to hunt!

There are a few things you need to think about when planning a lichen hunt.

  • Choose your location. This can be simple because lichen grows everywhere! It is certainly growing on trees in your neighborhood. Is there a local park you like to visit? Look for it on benches and big rocks.

  • Dress for the weather. How cold is it? Do you need long underwear or snowpants? Snow boots to keep your feet warm and dry?

  • Bring a hand lens/magnifying glass and/or camera. To the naked or unaided eye, many lichen species may look the same. It is a whole different world to view through a hand lens or magnifying glass. You can observe the many little features that make each species unique. You can also photograph lichen that you find.

  • Have a field guide. Here are two great resources with color photos of local species of lichen: The Field Museum of Natural History makes many wonderful guides, including this one on Chicagoland lichen species. Field Museum-Chicagoland Lichen Guide. Another great lichen guide is from our neighbors to the north, Common Lichens of Wisconsin. This guide also includes the most common substrate, or object the species is likely to grow on. You can print out a guide to use while you are outside. Or wait until you return from your hunt, pull a guide up on your computer and compare images to the photos you snapped or pictures you drew.

  • Use a nature journal, pencil and/or colored pencils. Depending on the weather, you may want to save this step for when you are back indoors as well. Get snuggled up with cozy clothes and a warm mug of cocoa and draw what you saw. You can use images from your camera or even from the field guides to re-create some common species with your colored pencils. Pay attention to detail. What are the differences in color and shape? In addition to drawing, you can write field notes. Where was it found? What was it growing on? How big was it? What other details can you describe?

So this December don’t be a couch potato waiting for warmer weather. Bundle up, get outside and go for a lichen hunt. There is a wonderful miniature world waiting for you to discover!


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