I forget, what is lichen anyway?
It's really simple. It's a really simple symbiotic organism of fungus and (often) blue-green algae. There are a gazillion versions of lichen. It often grows in really harsh environments, and can look like a small leafless plant, or grey green pealing paint, or a mass of golden hair. Or a lot of other things. If you've ever been on a mountain, above treeline, and seen a spread of something leafless in the sunshine on top of rock that wasn't dirt, it was probably lichen.
Lichen are not plants, but like plants, lichen cannot move on their own. Most lichen rely on wind to distribute their spores. Some types are too small to see with the naked eye. There are some very small low mass, high surface area lichen that can live indefinitely and reproduce while airborne. Have you tried the Wikipedia article? It's a short article. If you're curious, and I think you are, follow the links there to 'fungus', and maybe then to 'fungal prions' too.