Lichens

Although lichens may be small, they play an important role in the ecosystem. Lichens are great indicators of environmental health, especially in telling us about the quality of the air we’re breathing. Wildlife benefit from lichen by using it as food, shelter, and building materials. Humans have also developed different ways to use lichen.

Did you know that lichens are not plants? They are also not fungi! Lichens are formed by a partnership (a symbiotic, or mutual relationship) of fungus and algae and/or cyanobacteria. The fungus provides a structure for the algae to live in, while the algae provide food for the fungus. Cyanobacteria are bacteria that live in water environments and make their own food through photosynthesis. Cyanobacteria can also use nitrogen gas in the atmosphere into an organic form. Lichens’ main nutrients include nitrogen, carbon, and oxygen. There are three main body types of lichen–foliose, fruticose, and crustose.

1. Foliose lichens are flat and leaf-like. They usually have a top and bottom side.

2. Crustose lichens are crusty looking lichens that are often found on surfaces of rocks, soil, or even your roof! Sometimes it can be hard to tell the difference between the lichen and the base material it is growing on.

3. Fruticose lichens often have stem-like structure and have fruiting bodies. They have visible characteristics that can be stringy, hair-like, shrubby, or cup-shaped.

When you visit Katahdin Woods and Waters National Monument, take a pause, and notice the different types of lichen that are forming around you. Lichens have a wide range in size, shape, color, structure, places they live. There are more than 3,600 known species of lichen in just North America, and there is still much to be discovered in this diverse world of lichens. To help us understand more about lichens in the monument, take photos of what you see during your visit and engage in community science.