Distribution: N - Frl (Tretiach & Molaro 2007), TAA, Lomb. C - Abr, Mol (Nimis & Tretiach 1999, Caporale & al. 2008). S - Camp (Aprile & al. 2003b), Pugl.
Description: Thallus minutely subsquamuose to subfruticose but appearing subcrustose, homoiomerous, gelatinous when wet, dark olivaceous brown to black, of isolated or aggregated, button-like areoles densely covered in small, entangled cylindrical lobules, often forming up to 3(-5) mm wide, umbilicate cushions. Lobules to 0.4 mm long, 0.15-0.2 mm wide, minutely longitudinally striate, with globose hormocystangia at the slightly swollen apices. Apothecia very rare, laminal, immersed, hemiangiocarpic, with a pore-like disc and a thick thalline margin. Proper exciple very thin, of parallel hyphae; epithecium brownish; hymenium and hypothecium colourless, I+ reddish brown, K/I+ blue; paraphyses mostly simple, not apically thickened, adglutinated. Asci 8-spored, prototunicate, cylindrical, without a distinct apical apparatus. Ascospores 1-celled, hyaline, ellipsoid, 7-9 x 5-7 μm. Photobiont cyanobacterial (Nostoc, in short chains), the individual cells 4-5 μm wide. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on steeply inclined surfaces of hard calciferous rocks with some water seepage after rain, often in sites with cyanobacterial colonies.