Synonyms: Lecania nylanderiana A. Massal. var. coeruleorubella (Mudd) Zahlbr.
Description: Thallus crustose, rimose or areolate, thick, yellow-brown to brown-grey, densely covered in flattened to globose 45-65 μm wide, glossy blastidia which are often arranged in chains. Cortex c. 40 µm thick; medulla white, I-. Apothecia lecanorine, round or irregular in outline, 0.5-1.2 µm across, sessile or adnate, sometimes constricted at base, with a red-brown to black, but often grey-pruinose, flat to slightly convex disc, and a brown-grey, swollen, irregularly cracked to incomplete, blastidiate thalline margin. Thalline exciple thick, rich in algal cells; epithecium reddish-brown, with a granular epipsamma; hymenium colourless, 50-70 µm high, paraphyses simple or shortly branched and submoniliform in upper part, K/I+ blue, the apical cells swollen, 3-5 µm wide; hypothecium colourless or pale brown. Asci 8-spored, bitunicate, with a K/I+ blue tholus and a central non-amyloid area, Biatora-type. Ascospores (1-)3-septate, hyaline, narrowly ellipsoid, straight or curved, 14-25 x 4-4.5 μm, thin-walled. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on mortar and limestone on shaded walls; widespread in Europe, with a few, mostly historical records from the Eastern Alps (Austria); 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)