Distribution: N - Frl, Lomb. C - Marc (Nimis & Tretiach 1999).
Description: Thallus crustose, thinly episubstratic, grey-green to blue-green when dry, intensely green when wet, irregularly rimose to areolate, the areoles small, 0.1-0.4 mm wide, often delimited by a thin, white, arachnoid prothallus, sorediate. Soralia pale green, discrete to irregular, punctiform and to 0.3 mm across when discrete, developing from the surface or the margins of the areoles; soredia 30-50 μm wide. Apothecia rather rare, lecideine, sessile and constricted at base, 0.3-1.2(-1.5) mm across, beige, pink, pale red-brown to dark grey-brown, with a flat to convex disc, and a darker, initially thick, but soon excluded proper margin. Proper exciple pale orange-brown in outer part, more or les colourless within, the pigmented parts K+ purplish brown, composed of stout, densely compacted and branched hyphae; epithecium scarcely differentiated from the hymenium, colourless or pale yellow-brown; hymenium colourless in lower part, 80-95 μm high, I+ blue; paraphyses 1.5-2 μm thick at mid-level, mostly simple, the apical cells to 2.5(-3) μm wide; hypothecium colourless or pale yellowish. Asci 8-spored, cylindrical-clavate, Bacidia-type. Ascospores (1-)3-septate, hyaline, fusiform, (10-)12-19 x (3.5-)4-5 μm. Photobiont chlorococcoid, the cells 6-12(-14) μm in diam. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: thallus without lichen substances.
Note: a mild-temperate lichen found on calciferous and base-rich siliceous rocks in sheltered and humid situations below the subalpine belt; rarely collected, being often sterile.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)