Lichens, Moss and Fungi existed in the world before there were true plants. These are sensitive to changes in the environment, and so environmental students like to look for them and notice their type and condition. Lichen are often the first larger organisms to appear on a rock. Sometimes one kind of lichen grows on top of or beside another. Moss can start right on the top of lichens.
Fungi grow where there is organic material to decompose, in old dead wood, for example.
In areas where the air is healthy there are many different kinds of lichens and mosses. Lichen and moss in cities may only be tiny colored spots on stone or sidewalks. When moss and lichen are injured by poisons in the air, they turn white at the edges or tips, lichens turn white also in the center, and they stop growing. Take five or ten minutes to look at the guide books, if they are available, so you can recognize these growing organisms. Sketch your findings and enter them in the sheet below.