Distribution: N - TAA (Nascimbene 2008b), Lomb (UPS-L166849), Piem (Isocrono & al. 2004). C - Tosc, Sar. S - Camp (Aprile & al. 2003b), Bas (Puntillo & al. 2012), Cal (Puntillo 1996), Si (Grillo 1998, Grillo & Caniglia 2004).
Description: Thallus crustose, episubstratic, continuous or rimose, the surface granulose-warted, grey-green to greenish brown, often delimited by a white, fimbriate prothallus. Apothecia biatorine, sessile, pale cream-coloured to deep reddish brown or (rarely) black-brown when old, 0.2-0.6(-0.8) mm across, with an initially concave, then flat and finally convex disc, and a thin, usually paler, finally often excluded proper margin. Proper exciple dark brown or violet-brown brown in outer and upper parts, colourless within; epithecium pale brown, K+ purplish, scarcely differentiated from the hymenium; hymenium mostly colourless, 45-55 μm high; paraphyses mostly simple, 1-1.5(-2) μm thick at mid-level, the apical cells often swollen, 3.5-5 μm wide; hypothecium colourless or pale yellow in upper part. Asci 8-spored, cylindrical-clavate, approaching the Bacidia-type, but the ocular chamber wider, and the axial body never penetrating through the entire d-layer, surrounded by a narrow, darker amyloid layer. Ascospores 3(-7)-septate hyaline, needle-like, 20-45 x 1.5-2.5(-3) µm. Pycnidia rare, of two types: a) white, with 23-55 x 0.5-1 μm, curved conidia, b) brown, with 11-19 x c. 1 μm, curved conidia. Photobiont chlorococcoid, the cells 5-12(-14) μm in diam. Spot tests: thallus and apothecia K-, C-, KC-, P-, UV-. Chemistry: no lichen substances in thallus.
Note: apparently this is a holarctic lichen, found on periodically inundated or otherwise moist siliceous rocks, more rarely on lignum, in humid-shaded situations, with a wide altitudinal range.