Description: Thallus crustose-placodioid, episubstratic, lemon yellow to golden yellow, sometimes whitish-pruinose in central parts, forming 0.5-2 cm wide, at first orbicular, then irregular and often coalescing rosettes, with a verrucose-areolate to lobulate centre and more or less distinct, radiating marginal lobes. Lobes 0.5-1.5 mm broad, flat to slightly convex, contiguous to separate at margin, fused together towards the centre. Apothecia frequent, lecanorine, rounded, sessile and strongly constricted at base, 0.6-1.5 mm across, with an orange to brownish orange, concave to flat, smooth disc, a thick, orange to orange-red proper margin, and a thin, strongly white-pruinose, finally often excluded thalline margin. Epithecium orange-yellow, K+ red; hymenium colourless, c. 80 µm high; hypothecium colourlesss. Asci 8-spored, clavate, Teloschistes-type. Ascospores 1-celled, hyaline, thin-walled, spindle-shaped with pointed ends, 17-24 x 7-8 µm. Pycnidia orange-yellow, immersed. Conidia bacilliform. Photobiont chlorococcoid. Spot tests: thallus and apothecia K+ red, C-, KC-, P-, UV+ pale orange. Chemistry: thallus and apothecia with fragilin (major), emodin, parietin and other anthraquinones (minor).
Note: on soil, often on gypsaceous substrata in dry situations, mostly in the Mediterranean belt; to be looked for in Italy.
Growth form: Crustose placodiomorph
Substrata: soil, terricolous mosses, and plant debris