We've had a wood split rail fence for years along two sides of our property. It doesn't do much good for keeping anything in or out, and only serves to mark property boundaries in a pretty ordinary way. But something is happening on that fence that's anything but ordinary.
Lichens grow on the top side of several of the rails and they've been there for years. They always make me smile, just like the times I find a tiny red spider mite in the soil as I work in the garden. Just like when I know there are citronella ants in the soil before I actually see them because I can smell their lemony goodness.
I never took the time to look the lichens up to see exactly what they were until last year, when I discovered that they were Cladonia cristatella, commonly known as British Soldiers, so named for their red "coats."
Lichens consist of a fungus and an algae living together, in a symbiotic relationship. Each could survive without the other, but together they're better. The fungus provides a house for the algae and the algae produces food for the fungus.
In the case of British Soldiers, the red part of the fungus makes spores, which are dispersed by the wind. These spores can form a new fungus, but it won't become another British Soldier until it is joined by the algae. It also won't be red without the algae.
British Soldiers are a frutose lichen, which is an upright form of lichens that also tend to have bright colors. They grow on decaying wood, mossy logs, stumps, tree bases, and soil. They help break down old wood, as well as taking nitrogen from the air, and in these ways enrich the soil. Lichens don't do well in polluted areas, so lichens can be an indicator of good air quality.
Lichens grow very slowly and British Soldiers only grow one to two millimeters a year. The tallest part of these on our fence are about 10 millimeters tall. They won't make spores until they're about four years old.
Information gathered from http://www.fcps.edu/islandcreekes/ecology/british_soldiers.htm