Distribution: N - Frl, TAA (Nascimbene & al. 2007b).
Description: Thallus crustose, thin, usually continuous, grey-white to pale yellowish, Apothecia arthonioid, at first rounded, then ellipsoid, flat to slightly convex, to 1 mm across, angular or lobed, brown-black but usually white-pruinose at least in the marginal zone, often aggregated into star-shaped clusters. Proper exciple poorly developed; epithecium brownish; hymenium colourless, 50-70(-100) µm high; hypothecium colourless. Asci 8-spored, broadly clavate, semi-fissitunicate, with a large apical dome and a distinct ocular chamber, Arthonia-type. Ascospores 3-4-septate, hyaline, sole-shaped (with unequal cells), (12-)15-22 x 6-8(-9) µm. Photobiont trentepohlioid. Spot tests: thallus K- or K+ lemon yellow, C-, KC-, P-. Chemistry: unknown.
Note: a mild-temperate species of acid bark, especially of Abies, in humid montane forests. It is included in the Italian red list of epiphytic lichens as “Endangered” (Nascimbene & al. 2013c).
Growth form: Crustose
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)