Evernia prunastri, also known as oakmoss, is a species of lichen. It can be found in many mountainous temperate forests throughout the Northern Hemisphere. Oakmoss grows primarily on the trunk and branches of oak trees, but is also commonly found on the bark of other deciduous trees and conifers such as fir and pine.

Oakmoss is commercially harvested in countries of South-Central Europe and usually exported to the Grasse region of France where its fragrant compounds are extracted as oakmoss absolutes and extracts. These raw materials are often used as perfume fixatives and form the base notes of many fragrances.