Likin' Lichens

Lichens are some of the most common organisms in the forest. About anywhere you look you can find lichens.

Lichen on Tree

But some would argue that lichen isn't really an organism. Not a single one, anyway. A lichen is made up of at 2 separate organisms. It's a relationship between an algae and a fungus. The algae provides the chlorophyll to make food for the lichen, the fungus provides structure and moisture. Living together the fungus and algae create something that is very different from either constituent part.

Here in Florida and much of the South one of the most beautiful lichens we have is the Christmas lichen.

Christmas Lichen

Christmas lichen is roughly circular and has a nice red outline that makes easy to identify. A few other lichens have some red coloring, but none has it just on the perimeter.

Another interesting Florida lichen is usnea. Unlike Christmas lichen usnea is very widespread, found throughout most of the world. Usnea was used by the Seminoles for wound treatment. Putting usnea in a wound was supposed to keep it from getting infected. Seriously folks, don't try this at home.

Usnea

Usnea was once thought to damage trees. Orchard owners would remove usnea from branches as it grew. But we now know that it doesn't hurt trees. Instead it tends to grow on trees that are already in ill health.

The relationship between the fungus and algae has been long understood. Or at least everybody assumed it was pretty well understood. A small nit in that understanding is scientists were never able to create a lichen in the lab. They could take the species of fungus and algae known to create the lichen but they couldn't make them combine to create the lichen.

But an earthquake in the lichen scientific world has been rumbling for the last few years. A researcher named Toby Spribille first proved that at least some lichens contain 2 different fungi. The amount of the 2nd lichen was so small that it was overlooked for a couple of centuries. The initial combination seems to be the 2 different fungi. Only after they combine can they take in the algae that completes the formation of the lichen.

Other previously unrealized fungi combinations are now being found, allowing creation of previously known lichens. Now that they know where to look creating lichens is much easier. Lots of science fiction novels deal with the creation of new life forms. Now knowing that there's a 2nd fungus involved in very small quantities makes it easy to create lichens from their fungus and algae parts. Not exactly a frankenstein lab, but life creation in its own way.

This will be an interesting area of research over the next few years. Better understanding of the over 20,000 species of lichen is coming. Labs across the world are finding fungi combinations core to the lichen. A large step in understanding such common organisms doesn't come every day.

One minor clarification:  There are a few lichens that are a combination of a fungus and cyanobacteria, and even fewer that are fungus, algae and cyanobacteria. I didn't go deeply into this because it can become quite complicated. Let's leave it as a combination of fungi and algae for simplicity.