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Cladonia (order Lecanorales) A genus of lichens in which the thallus usually consists of a crustose or squamulose primary thallus (which may be evanescent), and a fruticose ‘secondary thallus’ called a podetium. Podetia may be erect, and branched or unbranched, or may be shaped like miniature cups or wine glasses (cup lichens). Apothecia, when present, are borne at the tips of the branches, or on the edges of the cups, and may be red or brown. Cladonia is a large genus consisting of over 300 species, found on the ground, on rocks, on wood, etc. See also REINDEER MOSS.