reindeer mossreindeer moss
any of various intricately branched, spongy lichens (genus Cladonia), esp. a gray lichen (C. rangiferina) eaten by grazing animals in the Arctic and, sometimes, by people
Any of several erect, grayish, branching lichens of the genus Cladonia of Arctic and boreal regions, especially C. rangiferina, constituting the chief source of food for reindeer. Also called reindeer lichen.