Description: Thallus subcrustose to small-squamulose, homoiomerous, subgelatinous when wet, ecorticate, dark reddish brown, to 0.3(-0.5) mm thick, forming up to 2 cm wide patches. Thallus anatomy paraplectenchymatous, the hyphae forming a large-celled network around the cyanobacteria. Apothecia formed in a tangle of generative hyphae, to 1 mm across, adnate, with a flat to convex, red-brown, shining disc, and a crenulated-squamulose thalline margin containing cyanobacteria. Thalline exciple c. 150 μm thick; proper exciple thin, 10-25 μm wide, of parallel hyphae; epithecium brownish; hymenium colourless, 125-150 μm high, I-, K/I-; paraphyses slender, sparingly branched, septate, gelatinized, not swollen at tips; hypothecium brownish. Asci 8-spored, cylindrical, bitunicate, rostrate, with a 1+ blue outer coat the apical part separated from the expanded amyloid rostrum by a non-amyloid zone. Ascospores 1-celled, hyaline, ellipsoid, 9-15(-17) x 4-8 μm. Pycnidia rare, immersed in warts. Conidia bacilliform, 4-5 x c. 1 μm. Photobiont cyanobacterial, chroococcoid (Gloeocapsa), surrounded by a reddish (in outer parts) to colourless (in inner parts) gelatinous sheath. Spot tests: all negative. Chemistry: without lichen substances.
Note: a cool-temperate to boreal-montane, perhaps circumpolar lichen found on siliceous rocks, especially in seepage tracks on on small pebbles in wet places, sometimes even on soil, usually in upland areas; much overlooked, and probably more widespread in the Alps.