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Wet Lichens and Dry Lichens by Rick Hollis

Lichens are marvelous things, composite organisms made up of an algae, a fungus and kind of yeast.

One the many things that I learned from John Pearson this fall*, is that under dry conditions the the fungal cells’ bright colors mask the algal cels and little or no photosynthesis occurs.  When lichens get wet, the bright fungal pigments fade, allowing the algal cells green pigments to show through.

Since then I have been meaning to do a little test to see if I could see this.  This fall I collected two lichens from my daughter’s yard in Indianapolis, one was a pale gray-blue and very crinkly
and the other was pale green and more leave-like.

I placed two pieces of each on the back of an old phone [black and waterproof], took them too the kitchen and put some water one of each.  A minute or two later, I soaked up the excess water and photographed them.  Elapsed time was a couple of minutes.  I then photographed them.   It is easy to see that both lichens greened up when wet.

An hour or so later the wet and green sides were indistinguishable.

* John’s talk, at FW Kent Park, was sponsored by Iowa Master Naturalists.

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