Found virtually everywhere in the world, lichens are the result of a symbiosis between an alga and a fungus. The alga supplies the carbohydrates needed for growth, while the fungus provides shelter for the plant. Evernia lichens attach to the branches of host trees. The furfuracea species, which often grows on pine trees, has a green top surface and a black bottom surface. Treemoss and oakmoss are not cultivated and are gathered by hand.