Buellia badia, the parasitic button lichen, is a dark chocolate-brown crustose areolate lichen of Europe, northern Africa, and North America that starts as a parasite growing on other lichens, such as Aspicilia phaea, gradually then becoming independent growing on rock (sometimes also on hardwood.[1] [2] Areoles may be contiguous or dispersed.[2] Lecideine apothecia are 0.3 to 0.9 mm in diameter with black discs, that are initially flat, then become strongly convex as they age.[2] Lichen spot tests are all negative.[1] There are no known secondary metabolites as of (2001).[2] It is similar in appearance and other ways to the chocolate brown Dimelaena californica, which also starts off as a parasite on other lichens, and has spores of similar shape, size, and internal construction.[2] D. californica has not been found on wood, is more preferential as to the lichens it starts growing on (usually Dimeleana radiate), and commonly has norstictic acid as a secondary metabolite.[2] Some think they should be included in a new, third genus.[2]