You may think that if you’ve seen one lichen, you’ve seen them all. Oh, so not so. Yes, many of them do resemble your common leathery grey-green patches plastered on trees like bark band-aids. But there are so many, many more. If you look around, they are everywhere, and they are gorgeous. Today I bring you a delightful seven-minute video with music showcasing some of the diversity of form and color in lichens, and I hope you will wait until you can take a little 10-minute break to relax and savor it.
Lichens are more or less co-ops between fungi and green or blue-green algae, which are photosynthetic microbes. The fungus makes the “house”, protects the alga from dessication, and absorbs minerals from the surface it’s living on, while the algal cells, sandwiched in between thick fungal layers in a cage of filaments, soak up rays to do the cooking. Because many of the algal species found in lichens can live quite happily on their own, (ever seen otherwise bare-looking tree bark glow green on wet days? That’s free living algae) scientists don’t actually agree over what the relationship is, exactly, between the fungus and the alga.
Has the fungus enslaved the alga, purposely keeping it barefoot and pregnant and locked inside its mycelial kitchen? Or are they best buddies homebrewing lichen compounds (the chemicals that make so many brightly colored) in the lichen frat house? Is the nature of the relationship more or less consistent for all algal species, or does it vary? These are fascinating questions which, to the best of my knowledge, are still not fully answered.
I have not forgotton about finishing up the Very High Life series, but life has intervened, and one weekend of busy-ness has turned into three in a row, and on top of that I remodeled my house and am writing a freelance story that is competing for my blog working time. I will not leave you hanging at 17,000 feet forever, I promise. But FYI, I may be posting less frequently and less lengthily for the next week or so.
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I think that the best definition of lichens that I’ve seen is by Trevor Goward, a lichenologist:
“Lichens are fungi that have discovered agriculture”