Lichens play a critical role in mineral nutrient cycling in many forests. We are just beginning to understand the diversity and importance of lichens in our natural systems. This and other ongoing work on Missouri lichens has resulted in the discovery of several species new to science, including two that have been named after the state of Missouri. You can identify three general types of lichens by their shape and appearance. The best known local examples of fruticose lichens are British soldiers, old man's beard and reindeer lichen.
Fruticose lichens are often the first to disappear when a natural habitat is disrupted.
Probably the most common type of lichen in Missouri is the foliose lichen. These are flat, typically green or gray lichens that can be abundant on trees and rocks, especially in the Ozarks. Crustose lichens are the most diverse and least noticed group of lichens in Missouri. Just as their name implies, crustose lichens often look like a thin crust on rocks, soil, trees, fenceposts, shingles and old, rusted iron on bridges. Some crustose lichens even grow inside rocks, occupying the microscopic spaces between rock crystals.