Thallus crustose, superficial, cracked to areolate, pale grey to chalk-white, often conspicuously thickened, densely white-pruinose (the surface appearing sugar-dusted), clearly delimited with a white prothallus. Anamorph: no information available. Teleomorph: ascomata apothecia, 2-5 mm diam., urceolate and initially immersed, the thallus tissues surrounding the erupted apothecia crenate and often appearing minutely toothed. Disc mid to dark grey, strongly pruinose. Hymenium 120-190 μm tall, hyaline, staining blue in iodine. Hypothecium ± hyaline. Interascal tissue of usually unbranched paraphyses with slightly swollen, pigmented tips. Asci 90-130 × 20-30 μm, cylindrical when young but clavate-ellipsoidal when mature, Lecanora type, 4-spored. Ascospores 25-40 × 10-17 μm, muriform and distoseptate with 4-7 transverse and 1-2 longitudinal septa, dark grey to grey-brown when mature, smooth, without an epispore, gelatinous sheath or appendages. Chemistry: thallus C+ red, K-, Pd-, UV- (lecanoric acid).