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U.S. Forest Service


Learn About Lichens

Lichens are interesting organisms. They are diverse, adaptable, functional, and little understood. They play an important role in our natural ecosystems and can let us know when those ecosystems are in trouble. Lichens are beautiful, especially when you view a lichen-drenched Douglas-fir or a colorful crust-covered cliff, and up close when viewed under a hand-lens or microscope.

Alectoria sarmentosa, witch's hair, on Douglas-fir trees

About Lichens

Learn to recognize lichens, the difference between lichens and other plants, and why lichens are important

Xanthomendoza mendozae

Lichen Biology

Learn about lichen structure, growth forms, and reproduction

Letharia vulpina, wolf lichen, on tree bark

Lichen Habitat

What are lichens' growth requirements?

Lichenologist using a hand-lens to identify a lichen


Find out about collecting and identifying lichens

Adult hummingbird with its young on a nest made of lichen

Did You Know?

Fun facts about lichens and their use

Cladonia cervicornis

Photo Gallery

Explore the forms and variety of lichens

Peltigera collina

Lichen Glossary

Find definitions of lichen-related terms

Map of the United States

Lichen Resources

Links, books, and guides about lichens