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What is a Lichen?

The following photo may look like an underwater scene, but I found this amazing lichen growing on a fallen limb.Lichens can be quite beautiful. You may find them draping from trees and covering boulders. They often grow alongside moss. Despite their plant-like appearance, lichens do not have real roots, stems or leaves and have little in common with true members of the plant kingdom. 

A lichen is a complex life form that is a fusion of a fungus and an alga. The partners maintain a symbiotic relationship: the alga photosynthesizes and provides food for the fungus, and the fungus helps the alga to grow and spread in different environments.

Lichens get all of their water and nutrients from their surrounding environment via air and rain. They are able to absorb everything in the air around them, including pollutants. Scientists can determine the levels of pollutants in the atmosphere and assess their ecological impact by extracting heavy metals and other toxins from lichen. 

Lichens are usually composed of layers of algae and fungi. The color of the lichen is often determined by whether it contains green algae or blue-green algae, as well as the color of the fungus. However, the components of some lichen are all mixed together in one uniform layer. The resulting growth is gelatinous, and these are called jelly lichens. Lichens can look like colorful crusts, or they may be leafy, flat, or full of ridges and bumps. They may look like little shrubs, or they may be long and hairy.

Lichens are an important food source for wildlife. They also provide nesting materials for birds. Fortunately, lichens do not harm plants on which they grow, although they may indicate poor plant vigor. If they are considered unsightly, prune out offending branches and stimulate new growth by mulching, watering, and fertilizing. Control on tree trunks is not necessary.

For more information, read my previous post about lichens:  Amazing Lichens

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Reader Comments (11)

I've always thought lichen were beautiful, not that I can recall ever seeing any in my own area. They have an other-worldly appearance.

June 11, 2018 | Unregistered CommenterKris P

Beautiful close-up pictures! I do appreciate lichen, they look so alien :-)

June 11, 2018 | Unregistered CommenterGoneTropical

I love this post! Lichen are amazing, aren't they? Much of our property is heavily wooded so there are lots of Lichen. You did teach me something......I never knew that nasty gelatinous stuff I stuck my hand in climbing trees, as a kid, was Lichen!

June 11, 2018 | Unregistered CommenterSally

Didn't know all this, so thank you, Deb, for some new information. In the first photo they look like sea weed. I love the look of these life forms, moss, fungi and lichens, and am fascinated by their story, which is rather strange, so different to plants.

June 12, 2018 | Unregistered Commentercatmint

Fascinating and beautiful, and usually a sign the air is relatively pure..

June 12, 2018 | Unregistered CommenterChristina

Hello Pam, great information and I love your picture of the lichen. They used to say if lichen was growing on the branches of a tree it was the sign of healthy air quality.

June 12, 2018 | Unregistered CommenterAlistair

Lichens are fascinating and so beautiful. Not unsightly at all! You have some extraordinary specimens there Deb.

June 14, 2018 | Unregistered CommenterDenise

I wonder, can we, eat lichen, as a garnish say?

June 14, 2018 | Unregistered CommenterDiana Studer

Very interesting! I know some people who are really fascinated by lichens, and now I can understand why.

June 15, 2018 | Unregistered CommenterJason

Lichen are amazing! I, too, remember hearing that lichen was a sign of clean air. When I was a kid and lived in Alaska, lichen that we called reindeer moss grew in the woods and we used to play with it. We always thought it was so pretty.

June 17, 2018 | Unregistered CommenterIndie

Your beautiful lichens are poster picture awesome. Great captures !

June 22, 2018 | Unregistered CommenterPatsi

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