Thallus wide-spreading, smooth, warted or ± dispersed in coarse irregular patches, continuous or ± rimose, chalk- or grey-white to grey, water repellent. Soralia and isidia absent. Photobiont Trentepohlia. Anamorph: conidiomata pycnidia, 50-200 µm diam., solitary, elevated or immersed, brown to black, rarely with a thalline margin. Conidia filiform, straight to curved, hyaline, aseptate. Teleomorph: ascomata apothecia, circular to elongate, wart-like, starkly white-pruinose with the discs often ± obscured by dense white pruina, embedded in a rounded or somewhat irregular, elevated stroma 0.1-0.5 mm diam, often constricted at the base, containing 5-15 apothecia. Discs exposed, starkly white-pruinose with the discs often ± obscured the pruina, often ± irregular in outline. Thalline margin level with disc, the hyphae richly branched, interwoven, hyaline, with crystals disappearing in K. Epithecium 30-40 μm thick, dark brown. Hymenium ca 80 μm tall. Hypothecium carbonaceous, extending down to the substrate, with brown pigement that is K+ olive-black. Interascal tissue composed of sparsely branched pseudoparaphyses, agglutinated in a I+ blue gel, but easily separable in KOH. Asci ca 70 × 16 μm, clavate, fissitunicate, thickened at the apex, with an internal KI ± blue ring, 8-spored. Ascospores 35-44 × 4-5 μm, narrowly fusiform, usually with one end tapering more than the other, curved, sometimes straight, 3-septate, hyaline, without an epispore, gelatinous sheath or appendages. Chemistry: thallus C–, K–, Pd+ orange-red, UV + cream-coloured (protocetraric and roccellic acids).