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The Lichens - A Lesson in Symbiosis

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I am not sure why lichens fascinate me.  Perhaps it is their exotic, alien appearance or their ability to survive in the most extreme conditions on earth.  I've seen them in the sub zero climate of Alaska and in the worst burning desert of the Middle East and Central Asia.  You can describe a lichen any way you like, but tough is the optimum word.  A lichen, however, is probably the most wonderful example of natural symbiosis in the world.  This is cooperation at a fundamentally simple level.  The organism is actually two organisms: a fungus and an algae combined.  The algae is a cyanobacteria also known as blue green algae.  The fungus part of the lichen provides an anchor to the substrate, and absorbs water and nutrients.  The algal part of the lichen converts these nutrients into useable carbohydrates through photosynthesis - a perfect marriage!  Lichens are more than pretty little things to look at, too.  The provide food and nesting material for many species of wildlife and have a wide range of medicinal properties.  Lichens provide food for man and animals, and are also used to make certain dyes as well. 

 

There are three basic kinds of lichens, each named for their particular shape and the manner in which they anchor themselves to the substrate:

  1. Cructose Lichens - These lichens are generally flat and are attached to the substrate as though squashed like a thin pancake

  2. Foliose Lichens - This type of lichen is recognized by its leafy, lettuce like shape

  3. Fruticose Lichens - This is a "standup" type of lichen that appears more plant like in form.

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British Soldier Lichen  British Soldier Lichen

 

An example of a fruticose lichen.  A common, but exceptionally pretty lichen is the British Soldier lichen named for the bright red "hat" at the top of the stem.  This lichen is found in wet climates on rocks or decaying wood.  I have often seen it growing amidst clumps of rich green moss.  It looks like a mysterious miniature forest.

 

Bulls Eye Lichen Bulls Eye Lichen

 

An example of a cructose lichen.  On the other end of the humidity spectrum is the Bull's Eye Lichen.  These photos were taken in the desert like conditions of Yakima, Washington.  Lichen survive in incredibly austere conditions.  Like most living things that encounter this type of life threatening climate they have the ability to effectively shut down and wait for better days.

 

Oak Moss Lichen Oak Moss Lichen Lettuce Lichen

 

Oak Moss lichen on the left and center grows profusely in the Northwest.  The Lettuce Lichen on the left looks just like its namesake and is an example of a foliose type lichen.  I wonder how it tastes.

 

Rock Lichen  Rock Lichen

 

These rock lichens are very noticeable all over the Northwest.  On closer inspection several varieties are revealed.  Can you name the lichen types in the photo?

 

Reindeer Moss Reindeer Moss Reindeer Moss

 

Down south they call this "Reindeer Moss."  Probably in the same genera as our tree dwelling Oak Moss lichen; the fungal structure is very similar.

 

If you are fellow lichen lover and feel, as I do, oddly attracted by these interesting manifestations of earth life you are not alone.  There are several organizations for people like us and a number of great sites for further study.  Here is a great one:  http://www.lichen.com/index.html

Birds  Mammals  Reptiles  Amphibians  Fish  Invertebrates  Library  NWWOL Online Store Home

Mission  Editor Bio  Site Map   Contact   Wildlife Park Links  Further Study  Wild Employment  Northwest Trek

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