Synonyms: Lecanora argopholis var. ocellulata (Arnold) Jatta; Lecanora cenisia var. gangaleoides (Nyl.) Harm.
Distribution: N - Ven, Lig (Brunialti & al. 1999, Watson 2014). C - Tosc, Umb (Panfili 2000b, Ravera & al. 2006), Laz (Roccardi 2003, Genovesi & al. 2011), Abr (De Angelis & al. 2003), Sar (Nöske 2000, Rizzi & al. 2011, Giordani & al. 2013, Neuwirth 2018, Brackel & Berger 2019). S - Camp (Garofalo & al. 1999, Aprile & al. 2002, Catalano & al. 2016), Cal (Puntillo 1996), Si (Ottonello & Romano 1997, Grillo 1998, Grillo & Caniglia 2004, Ottonello & al. 2011).
Description: Thallus crustose, episubstratic, rimose-areolate to verrucose-areolate, whitish to whitish grey, often with a yellowish hue, sometimes delimited by a thin whitish prothallus. Lower part of medulla, especially below the apothecia, most often orange, K+ purple. Apothecia lecanorine, sessile, slightly constricted at base, 0.5-1.5(-2) mm across, with a black, flat to convex, epruinose disc, and a persistent, entire or rarely flexuose, smooth thalline margin. Thalline exciple corticate, the medulla with large crystals insoluble in K; proper exciple colourless, with crystals soluble in K; epithecium greenish brown to greenish black, K+ green, N+ violet-purple, without crystals; hymenium pale olive-green, 70-100 µm high, not inspersed with oil droplets; paraphyses 1-1.5 µm thick in lower part, not or only slightly thickened at apex, the apical cells to 2.5 µm wide; hypothecium colourless to very pale brown, not inspersed. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, 11-16 x 6-9 µm, the wall <1 µm thick. Pycnidia immersed, cerebriform. Conidia filiform, 13-17 µm long. Photobiont chlorococcoid. Spot tests: thallus K+ bright yellow, C-, KC-, P+ yellow-orange to red. Chemistry: atranorin (major), chloroatranorin (minor), gangaleoidin with ist accessories (major), and skyrin (minor).
Note: a mild-temperate lichen found on base-rich, but lime-poor siliceous rocks in sheltered situations, often in underhangs; mainly Tyrrhenian in Italy. Several records from the Alps, e.g. those cited by Isocrono & al. (2003) are not accepted here.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)