Description: Thallus crustose, bright yellow-pruinose, mostly reduced to small (0.15-0.3 mm in diam.), scattered warts containing an apothecium. Apothecia frequent, perithecioid, rounded, without a thalline margin but semi-immersed in the warts, 0.15-0.25(-0.3) mm across, with a concave, not exposed disc (the warts opening though a small pore), the margin 30-45 μm thick in upper part, 15-25 μm thick in lower part, colourless in section. Hymenial gel I+ red; paraphyses absent, substituted by richly branched, easily detached periphyses arranged around the ostiole and on the sides. Asci many spored, flask-shaped, persistent, thin-walled, the wall I+ pale blue, the base I+ brownish red, not thickened at apex. Ascospores 1-celled, hyaline, oblong-obtuse, slightly constricted in the middle, thin-walled, 3-4(-5) x 1-1.5 μm. Pycnidia, rare, immersed in the warts, often yellow-pruinose in upper part, with a colourless wall. Conidia oblong-obtuse, simple to 2-septate. Photobiont absent or chlorococcoid, rarely present only at the base of the thalline warts. Spot tests: thallus and apothecia K-, C-, KC-, P-. Chemistry: yellow pruina with pulvinic acid derivatives.
Note: a rarely-collected but apparently widespread ephemeral species of siliceous rocks and, occasionally, rotten wood, mostly in upland areas.