What is a lichen?
Definition: A lichen is a composite organism that arises from algae or cyanobacteria (or both) living among filaments of a fungus in a symbiotic relationship. The combined life form has properties that are very different from the properties of its component organisms. Lichens come in an infinite array of colors, sizes, and forms.
Accordingly, there are various types of lichens. . .
Macrolichens – (Definition)