Rock-shield Lichen (Xanthoparmelia). A lichen that I commonly see up here growing on rocks. An incredible organism that is a symbiotic partnership between a fungus and an alga.

I’ve become fascinated with lichens, but still I’m struggling to understand them. Not a plant, not an animal but an organism. There are about 3,600 species of lichens in North America, and more are being discovered every year.