Although lichens are sometimes mistakenly thought to be a fungal disease, they are actually the combination of two different organisms. Fungal cells make up the main body and structure of each lichen, and algae or cyanobacteria give it its green or blue color. The fungal part of a lichen is not capable of creating its own food, thus it relies on the photosynthesis in the algae cells for the energy it needs to grow. In turn, the fungus provides the algae with water and minerals and prevents it from drying out.
