Distribution: N - Ven (Lazzarin 2000b), TAA, Lomb (De Vita & Valcuvia 2004), Piem (Isocrono & al. 2004), VA (Piervittori & Isocrono 1999, Isocrono & al. 2008), Lig. C - Tosc (Ravera & al. 2019a), Sar (Rambold & al. 1994, Rizzi & al. 2011, Giordani & al. 2013).
Description: Thallus crustose, episubstratic, to 0.5 mm thick, areolate, without a distinct prothallus. Areoles up to 1.3-1.4 mm wide, contiguous, flat, whitish to grey, rarely grey-brown, dull. Apothecia pseudolecanorine to lecideine, innate to adnate, 0.3-1 mm across, with a black, flat to slightly convex disc and a black, often sinuous proper margin. Proper exciple colourless, 10-15 µm laterally, to 15-20 µm in upper part; epithecium reddish brown; hymenium colourless, 80-110 µm high; paraphyses 1.5-2 µm thick in lower part, conglutinate, the apical cells to 3-3.5 µm wide, immersed in a dispersed pigment; hypothecium colourless to pale brown, 70-180 µm high. Asci 8-spored, clavate, Lecanora-type. Ascospores 1-septate, brown, ellipsoid, 13-18 x 7-11 µm, with rugulate-ornamented walls, Milvina-type, with ontogeny of type A (apical wall thickening after septum formation). Pycnidia immersed in thallus. Conidia bacilliform, 5-6 µm long. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: zeorin.
Note: a temperate to tropical, widespread species known from from southern Africa, Asia, Australia, North and South America, Macaronesia and Europe, found on seepage tracks of (mostly) base-rich, hard, smooth metamorphic rocks, often along mountain creeks. The species is widespread in the Alps, but has been also reported from the Mediterranean mountains.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)