With the garden covered in snow, I have to really hunt to find color outdoors. This lichen on the Magnolia was all I found, but what a find. It's taken winter blahs to make me look closely to see the beauty that's been there all along.
Lichens are symbiotic organisms, made up of a fungus and either an alga (the singular of algae) or a cyanobacteria. The fungi obtain water and minerals, while the other parts provide energy through photosynthesis. Lichen can grow on bare rock and structures. While they contribute to weathering of rocks, they don't harm the trees on whose bark they live. Lichens can survive in harsh environments and provide a food source for some animals of the arctic tundra. There are different species of lichen, some of which have been used in medicine and as dyes. But that's not what's most of interest to the gardener. Lichens are an indicator of good air quality, as lichen is very sensitive to pollution. If you have lichen growing on your trees, rocks or other surfaces, that means you have pretty clean air, which is something to really like.