If you spend any time at all outdoors in Louisiana, you walk past them all the time. Tree trunks and rocks are among their favorite substrates, but most any long-exposed surface will do.
Next time, stop and look. How many of the 17,000 species worldwide can you find in a single 6 x 4 patch?
In fact, every lichen is at least two species–a fungi and an alga or a cyanobacterium, or both–living in close symbiotic relationship. Count them if you can!
Divine complexity incarnate in the most #humble of creatures.