Description: Thallus crustose, thinly episubstratic or partially endosubstratic, continuous to usually areolate, pale grey, brownish or grey-green, more intensely green when wet, with yellowish to yellow-green, intensively green when wet, 0.2-0.4 mm wide, concave to convex, well-delimited (never confluent), punctiform soralia with very fine, farinose soredia. Apothecia very rare, biatorine, 0.2-0.4(-0.7) mm across, with a pale orange to brown disc and a thin, usually paler proper margin. Epithecium colourless; hymenium colourless in upper part, brown in lower part, c. 70 µm high; paraphyses mostly simple, c. 2 µm thick at mid-level, the apical cells up to 3.5 µm wide; hypothecium colourless to pale brown. 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 a I+ red-brown, K/I+ blue outer layer, the ocular chamber relatively small, Biatora-type. Ascospores (0-)1(-2)-septate, hyaline, narrowly ellipsoid, 12-15 x 3-4 µm, thin-walled. Pycnidia immersed, reddish-brown around the ostiole. Conidia filiform, 13-19 x c. 1 µm. Photobiont chlorococcoid. Spot tests: thallus and soralia K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on bark of deciduous trees in different forest types; widespread in the Northern Hemisphere and also in the Alps, but not common; to be looked for in Italy.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)