Thallus crustaceous, verrucose to subareolate with small peripheral lobes. Photobiont: . A few species exist as parasymbionts on other lichens. Apothecia sessile or immersed in thallus. Excipulum of variable thickness, blackish-brown and formed of densely interwoven, sclerotized hyphae. Mazaedium well-developed. Asci obovate to cylindrical, always formed singly, dissolving at early stages. Ascospores 1-septate, dark brown, with thick walls. Spore wall often with distinctive ornamentation. Chemistry: Containing β-orcinol depsides and depsidones, and tetronic acid derivatives.