Distribution: C - Laz (Trinkaus & Mayrhofer 2000).
Description: Thallus crustose-placodioid, white, with radiating marginal lobes, forming orbicular rosettes to c. 2 cm inm diam. Lobes 0.4-1 mm broad, 5-8 mm long, elongate, flattened to weakly convex, strongly white-farinose -pruinose. Apothecia frequent, lecideine, sessile, 0.4-0.8(-1.2) mm across, with a black, flat to slightly convex, sometimes pruinose disc, and a thin, smooth, finally excluded proper margin. Epithecium yellowish brown; hymenium colourless. 50-70 µm high; paraphyses capitate, the apical cells with a dark cap; hypothecium brownish. Asci 4-spored, clavate, Bacidia-type, distinctly thickened at apex, with a I+ blue tholus, the outer gelatinous coat I+ pale blue. Ascospores 1-septate, constricted at septum, brown, ellipsoid, (10-)11-16(-19) x (4.5-)5-8(-8.5) µm, Buellia-type, with a very finely warted wall. Pycnidia dark, immersed. Conidia bacilliform, 5-8 x 1-2 µm. Photobiont chlorococcoid. Spot tests: thallus K+ yellowish red to very rarely K-, C-, KC-, P+ orange or P-. Chemistry: atranorin and variable amounts of norstictic acid.
Note: a mainly western European species growing on calciferous or gypsicolous soil in dry grasslands. According to Spribille & Wagner (2016), it is presently extinct over much of its former range: the only verifiable extant populations at present are in the Vågå region of Norway, where only two of three historical sites have been confirmed, and even these are in sharp decline.
Growth form: Crustose placodiomorph
Substrata: soil, terricolous mosses, and plant debris