Cladonia rangiferina, also known as reindeer lichen (c.p. Sw. renlav), lat., is a light-colored, fruticose lichen belonging to the Cladoniaceae family. It grows in both hot and cold climates in well-drained, open environments. Found primarily in areas of alpine tundra, it is extremely cold-hardy. Reindeer lichen, like many lichens, is slow growing (3–5 mm per year) and may take decades to return once overgrazed, burned, trampled, or otherwise consumed. A similar-looking species also known by the common name Reindeer lichen is Cladonia portentosa.