Description: Thallus crustose, episubstratic, 0.2-0.4 mm thick, pale green or greenish grey, matt, granular-verrucose to minutely subsquamulose, forming patches up to 10 cm in diam.; verrucae or squamules small, 0.1-0.2(-0.3) mm in diam., convex, densely crowded and frequently overlapping, rarely finely dissected, dissolving into poorly delimited, 0.3-0.7 mm wide soralia, the soredia 20-40 μm across, sometimes gathered into 30-90 μm wide consoredia. Apothecia biatorine, rounded, sessile with a strongly constricted base, 0.3-0.7(-1.2) mm across, with a beige to reddish brown, strongly convex, epruinose disc, and an indistinct, light beige, soon excluded proper margin. Proper exciple colourless, 35-90 μm wide laterally, 100-280 μm wide basally, of radiating, weakly branched and anastomosing hyphae with cylindrical, 1-2.5 μm wide lumina, the lumina of apical cells up to 3 μm wide; epithecium scarcely differentiated from the hymenium; hymenium colourless or pale yellow, 40-55 μm high; paraphyses simple or sparingly branched and anastomosing, the lumina 1-1.5 μm thick at mid-level, the apical cells 1.5-3.5 μm wide. Asci 8-spored, clavate, with a K/I+ blue apical dome penetrated by a narrow, K/I- apical cushion surrounded by a narrow, deeply K/I+ blue zone, the wall K/I- but surrounded by an I+ red-brown, K/I+ blue outer layer, the ocular chamber relatively small, Biatora-type. Ascospores 1-celled or rarely 1-septate, hyaline, ellipsoid, (8.5-)11-14(-19.5) x (3-)3.7-4.5(-5.5) μm. Photobiont chlorococcoid. Spot tests: thallus K-, C- or C+ reddish, P+ orange-red. Chemistry: thallus with gyrophoric acid, argopsin, and norargopsin (traces).
Note: on the base of coniferous trees near treeline; most records from the Alps (all outside the Italian territory) are historical; to be looked for in the Italian Alps.