A symbiotic union.

I had lots of thoughts about today's blip and DDW's challenge - union.

Since I used the gearhead side of my brain yesterday, today I decided to go all plant guy on my blip.

A symbiosis is a type of union that is advantageous to both organisms. Here we have something that everyone likely sees everyday, but pays little attention - a lichen. Lichens are commonly found growing on rocks, headstones, and tree bark, and is a plant comprised of two disparate entities growing as one. A lichen is a symbiotic union between a fungus and an alga (i.e. sea weed for lack of a better term).

I know nothing about lichens, except the few words above, but what I do know is that you are likely looking at several different species of lichens growing on ~ 6 square inches of rock.