Description: Thallus crustose, well-developed, episubstratic, granular to minutely verrucose, bright green, rarely endosubstratic and poorly visible. Apothecia stalked, pin-like, black or sometimes with a brown pruina on the lower side of the capitulum. Stalk black, epruinose or brown-pruinose in uppermost part, (0.6-)1-2.2 mm high, the central part of sclerotized, dark, irregularly interwoven to periclinally arranged hyphae, the outer part slightly paler and often with a translucent, non-amyloid, gelatinous coat. Capitulum lenticular, 0.4-0.7 mm across, with a well-developed, cup-shaped exciple of anticlinally arranged cells; mazaedium well developed, black; hypothecium blackish brown, with a convex upper surface. Asci clavate, formed singly, dissolving early, with biseriately arranged ascospores. Ascospores 1-septate, usually restricted at septum, dark brown, ellipsoid. 11-14 x 6-7 µm, with a thick, ornamented wall, the ornamentation first of spirally arranged ridges, later irregularly cracked-areolate. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-; brown pruina K+ red (needle-like crystals); ascomata I- in all parts. Chemistry: thallus with rhizocarpic acid and epanorin.
Note: a holarctic, temperate to boreal-montane lichen found on Abies and Picea, but also on the rough bark of old oaks in humid areas; certainly ranging throughout the Alps, rarer in the Apenninnes.