Distribution: N - Frl (Henssen & Tretiach 1995), Ven (Nascimbene & al. 2021), TAA (Nascimbene & al. 2022).
Description: Thallus small-fruticose, filamentous, homoiomerous, gelatinous when wet, dark brown to almost black, sometimes grey-pruinose, consisting of up to 0.2 mm thick and up to 5 mm long, furcate, adpressed, entangled branches, forming up to 3 cm wide, small carpets or loose, flattened cushions. Apothecia rare, laminal, developing from pycnidia, globose, semi-immersed, to 0.2 mm across, with a brown, finally convex disc and a thalline margin. Proper exciple very thin, of parallel hyphae; epithecium brownish; hymenium and hypothecium colourless, the hymenium 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, subglobose to broadly ellipsoid, 10-14 x 8-11 μm, with a gelatinous perispore which dissolves in K. Pycnidia dark, immersed, pyriform. Conidia bacilliform or fusiform, 4-5 x 1-1.5 μm. Photobiont cyanobacterial (Nostoc), the individual cells arranged in short chains, 4-5 μm wide. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on steeply inclined surfaces of calcareous or basic siliceous rocks in seepage tracks, mostly in humid areas, perhaps more widespread in the Alps.