“Has a squamulose primary thallus with fruticose podetia that grow up from it”

WHAT THE……????

With descriptions like that, It’s no wonder that so many people don’t bother to learn about lichens.

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The quote above, found in “A Field Guide to California Lichens”, was taken from the caption on a picture of one of my favourite group of lichens, the Cladonias, commonly called the pixie cup or trumpet lichens.

It is true that in order to properly classify and identify a lichen with reasonable certainty, you might need to know all that scientific jargon above.

But there are lots of common lichens that are easily distinguished and can be identified by their pictures in popular field guides to plants like this one.

And the feature picture on the cover of that book is also one of pixie cups.

Here’s a picture I took of a Cladonia in my neck of the woods, British Columbia. It’s growing on the bark of a nice old Douglas Fir tree.

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I can just imagine a group of pixies sitting on them smoking their pipes and having a gay old time talking about what all the big people are missing out on! Photo by Rich Sobel

So without any further ado, here’s 10 reasons, in no particular order, why you should learn to love lichens

1- Lichens Are Beautiful to Look At


This is what first attracted me to them. They come in all different shapes, forms, sizes and colours. Here’s a nice smattering of lichens I found on a rock during my recent walking trip on the Isle of Arran in Scotland.

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There’s at least 4 different kinds of lichen on this rock. Photo by Rich Sobel

I’ll bet you can find similar collections in your own neighbourhood.

2- Act as Environmental Indicators

Lichens are very sensitive to environmental changes and are often used to monitor air quality by the USDA Forest Service.

Some species grow almost exclusively on the bark of ancient trees and are indicators of old growth stands.

They are able to extract nitrogen from the air (commonly called “fixing it”) and make it available to plants. This is especially important in many deserts and in Pacific Northwest rain forests.

3- Start to Break Down Rocks

Lichens are usually the first visible creatures we can see that colonize rocks. They form tightly adhering patches in cracks and on the surface. Because these patches are very thin and don’t have any loose ends, they look like a crust and are referred to by people who study lichens as crustose lichens. (HehHeh, snuck in a scientific term on ya :)

These patches “digest” rocks and form tiny crevasses that water can collect in. When the water freezes and thaws, it starts to permeate and further break down the rock.

Which helps to build soils.

4- Help to Build and Stabilize Soils

Lichens are often a major component of cryptobiotic soils. Huh?!

Another interesting term derived from the Greek term “kryptos” which means “not immediately seen” or “secretive” and “biotic”, which refers to the living organisms present in a system. So there are a bunch of living organisms (algae, fungi, mosses, bacteria, lichens, etc) that you don’t see that release gelatinous substances that bind the grains of inorganic soil into a dense matrix.

This matrix stabilizes the soils and also helps to make nitrogen, carbon and other nutrients available to plants to help them grow.

5- As Food, Nesting Materials and Camouflage for Animals

Some lichens are quite leaf-like or form long strands and are used by animals to help build their nests.

You may have heard of reindeer moss, which Northern caribou, moose and deer eat. It is actually another one of the Cladonia species of lichen, with a slightly different form, that grows in alpine tundras in Canada and Scandinavia among others.

Some insects have evolved their appearance to resemble lichens, like this one sitting on a patch of lichen.

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Photo by Doug Ladd taken from here.

6- Provide Food for People

The Alaskan Dena’ina use reindeer moss for food after softening it by boiling and either eat it plain or mixed with other foods like berries, lard or fish.

And that’s just one example. If you search the internet, you can find lots of other lichens that humans have used as food.

7- Used to Make Colourful Dyes

Indigenous peoples have a tradition of making dyes from lichens for clothing and baskets. When mixed with water or pine sap they provide a variety of colours; brown, red, green, orange, yellow and purple are the most common.

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8- Lichens Can be Poisonous

Some lichens produce chemicals that are toxic to people and other animals. This means you can’t just pick up a lichen and eat it! Ya gotta know which one it is first, just like with mushrooms.

Some people are allergic to specific lichens.

9- They Have Medicinal Qualities

Many lichens have potent antibiotic properties

In the Eastern Himalayas, some indigenous people use reindeer moss to remove kidney stones.

The Alaskan Dena’ina use the juice from boiled reindeer moss to treat diarrhea.

10- Grow Almost Anywhere

Rocks, soil, trees, rotten wood, glass, walls, you name it!

In dry areas like Southern California, they can collect moisture from fog thus increasing the effective precipitation.

You often see them on older wooden fence posts

There you have it. Ten good reasons to like lichens.

I hope you enjoyed this short foray into the field of lichens (all puns intended :)

In future posts I’ll talk more about the biology of these fascinating creatures.

And since I love taking pictures of lichens here’s a couple more to feast your eyes on.

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Taken in Cathedral Lakes Provincial Park in British Columbia. Photo by Rich Sobel
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Taken in Cathedral Lakes Provincial Park in British Columbia. Photo by Rich Sobel

Until we talk again,


P.S. That squamulose primary thallus is just the mat of lichen “tissue” from which the pixie cups (podetia) grow up from. The thallus is the main body, hence primary, and squamulose refers to the small, scale-like lobes (squamulae) that lift up at the edges of the thallus and are where the podetia form.

Hey! Are you interested in biology news and fascinating/ cool stories — for yourself or to share with your friends or kids? Then grab my “3 Fascinating Creatures” ebook here and sign up to get my weekly newsletter. You won’t snore while reading it, I promise!

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Rich writes about fascinating creatures and biological issues that affect our everyday lives. Subscribe and get your free ebook at www.biology4everyone.com.

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