Evernia Prunastri Oakmoss is a species of lichen found in forests in many locations in the northern hemisphere including North America and Central Europe. A dark green colour. It grows on the trunk and branches of oak trees and can also be found on other deciduous trees. With a strong top note, and mossy base notes, this essential oil is often used in high class perfumery. It's a fixative which helps to sustain the fragrance and also adds a lovely, earthy quality.