liking lichen

lichens are miniature ecosystems made of fungus and an algae and/or cyanobacteria. these different life forms work very closely together, with the algae or cyanobacteria sitting inside the fungus. the algae or cyanobacteria provide the fungus with sugars made from sunlight, and the fungus provides the home for both of them. lichens get their nutrients from the air. because lichens have no roots , they cannot filter what they absorb, so whatever is in the air is taken straight inside. if there are pollutants, it can accumulate in the lichen and can become toxic very quickly. next time you are on a walk, take a look around for the types of lichen that grow in your area. as a rule of thumb, the smaller the size and the fewer the variety of lichens in an area, the more polluted is the environment.

common sunburst lichen (Xanthoria parietina)