Thallus 1-3 cm diam., orange-yellow to pale yellow or whitish, sometimes rosette-like but often irregular and fragmented, ± placodioid. Marginal lobes neat, clearly differentiated, longer than broad, mostly over 1 mm wide, remaining ± discrete or often overlapping especially towards the centre, which often becomes verrucose-bullate with age, ± coarsely pale pruinose. Schizidia variably developed; in most populations part of the thallus surface is given over to their production which when shed, exposes the white medulla. Photobiont chlorococcoid. Anamorph: not known. Teleomorph: ascomata apothecia, often present, 0.5-1.5 mm diam., erumpent through the upper thallus layers, at first concave with an irregular thalline exciple, becoming flat or shallowly convex with a ± excluded margin, deep orange to yellow, contrasting with the paler thallus. Asci clavate, the upper part with a thickened wall and a strongly blueing outer layer, 8-spored. Ascospores 9-12 × 3.5-5 μm, 0(-1)-septate, ellipsoidal, pyriform or clavate, not polarilocular, hyaline. Chemistry: thallus K+ purple (parietin and its precursor emodin), UV± dull pale orange (fragilin, caloploicin), apothecia K+ purple (physcion).
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