What is lichen? Great question, I’m glad you asked – for lichen is a bit of a strange thing.
What is Lichen?
First of all, let’s identify what lichen looks like. It’s that strange crust-like substance that forms on rocks and trees in the forest. You see it all the time, but it hardly gets any recognition. It is almost always a bluish greenish or orange – yellow color.
Lichen is very slow growing, and yet it covers 6% of the Earth’s surface! There are nearly 200,000 species of lichen and they are found just about everywhere. From the frigid arctic tundra to the hot dry deserts, and everywhere in between. Scientists believe that lichens may be some of the oldest living things on the planet and have dated one to 8,600 years old, making it the Earth’s oldest living thing!
OK, but what IS Lichen?!?
Right, so now that we have talked about lichen, and we can all agree we do know what it is. As in if I took you out into the woods here in the Green Mountains of Vermont and asked you to find me some lichen, you probably would eventually find the lichen. I don’t think you would confuse it with a plant or a mushroom.
But what IS lichen?!? OK, at this point you may be wondering why I keep asking that even tho it would seem we have already identified what lichen is. Have we though? Is lichen a plant? No. Is lichen a fungus? Nope. Is lichen a bacteria? Nuh-uh. Well, actually, it is all of the above and none of the above.
You see, this is getting weird right? Lichen is what’s known as a composite organism. This mean it is not just one organism or species, and is made up of two or more. Lichen is most often made up of a fungus, and a photosynthetic cyanobacteria. The fungus helps protect the bacteria, and the bacteria makes energy for the fungus from the sun – just like a plant. Often, a third or fourth species, such as yeast, will also be present among the lichen – further complicating things.
So then, I think we can easily enough understand what a lichen is. It is an entity that is made up of 2 or more species (at least one fungus, and at least one photosynthetic bacteria) that live together in a mutualistic way. The problem is that you can’t really call a lichen a species, or even an organism for that matter.
Even the scientific community sort of hit a roadblock on how to classify lichen. They DO sort and identify different lichens by calling them different species names, and yet at that same time recognize and caution that they are not actually species. This is just funny to me, and a great example of science failing to control nature.
Why I’m liking Lichen
I’m liking lichen particularly right now because it is stick season (see last post) in Stowe Vermont. As I wrote about in the last post, perhaps stick season’s most distinct characteristic is the greyness of it all.
Yet among all this grey, there remains one vibrant source of color. This strange thing (it is not an organism or species), somehow persists and finds its time to shine. Indeed, I challenge you to find anything brighter than a lichen during the cold Vermont November. And that is why I’m liking lichen right now – it is a light, when all else is dark.
