Parmelia is a genus of lichenized fungi, commonly found on tree bark, rocks, and soil. These organisms are known for their distinctive leafy or crust-like appearance and play a crucial role in ecosystems by contributing to soil formation and providing habitats for various microorganisms. The genus is characterized by its greenish-gray to brownish thallus, which can be flat or raised. Parmelia species are sensitive to air quality, making them useful indicators of environmental health. They are also used in traditional medicine and as natural dyes in some cultures.