Critter Chronicles: A Symbiote

I've decided that, for the purposes of this blog, "critter" includes anything alive -- animals, plants, and those that are somewhere in between.

While waiting for buses yesterday, I was noticing the lichenbs growing on trees by the bust stops. One in particular, a locust, had three different types of lichens growing on it, one green, one gray, and a couple of small patches of golden orange.

And what, exactly, is lichen? you may ask. From the U.S. Forest Service:

Lichens are a complex life form that is a symbiotic partnership of two separate organisms, a fungus and an alga. The dominant partner is the fungus, which gives the lichen the majority of its characteristics, from its thallus shape to its fruiting bodies. The alga can be either a green alga or a blue-green alga, otherwise known as cyanobacteria. Many lichens will have both types of algae.

There are about 3,600 species of lichen, and they take various forms -- low-growing, crusty-looking habits, branching, filamentous, you name it. The Field Museum a while back, had a small exhibition on lichens that was very interesting. One of the examples was the door from an old pickup truck that was covered in lichen. They'll grow pretty much anywhere -- I've seen them on trees, on rocks, on old scrap metal that's been lying outside -- all sorts of places.

Fascinating critters.