Lichens grow everywhere around the world. They are widespread because they are able to live and grow in some of the harshest environments on Earth, from arid desert regions to the Arctic; in fact, in Antarctica more than 350 species of lichens grow but only around two species of plants. Lichens grow on bare soil, tree trunks, rocks, fence posts, buildings, and on alpine peaks. Some lichens are so tiny that they are almost invisible to the naked eye; others like reindeer “mosses”—actually a lichen—can cover acres of land with ankle-deep growth. One species of the genus Verrucaria even grows underwater as a submerged marine lichen.