Lichen is a group of lower plants, or rather, a symbiosis of fungus and algae. Lichens can grow even in the harshest and most unfavorable conditions – high in the mountains, on rocks, tree bark. They successfully grow and develop even at low temperatures, low humidity and lack of nutrients. Lichens play an important role in soil formation. Lichens are used in folk medicine. Scented raw materials for the perfume industry are obtained from some types of lichens (for example, oak moss, Evernia prunastri and others). The smell of lichen gives the fragrance a cool, moist, slightly green, mineral and earthy orientation. Lichen notes are most often used in the base of the perfume, especially in chypre compositions.