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.

[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.

[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.