Description: Thallus crustose, endosubstratic, poorly evident. Apothecia short-stalked, pin-like, 0.5-1 mm high. Stalk black in lower part, bright yellow-pruinose in upper part, of periclinally arranged, medium brown hyphae. Capitulum to 0.3 mm across, obconical to obovoid, yellow-pruinose in lower part, with a well-developed excipulum of periclinally arranged, medium brown hyphae. Mazaedium well-developed, brown; hypothecium medium brown, obconical, with a flat upper surface. Asci cylindrical, either formed singly or in chains, dissolving early, with 1- to 2-seriate ascospores. Ascospores 1-celled, brown, globose, 5-8 µm wide, the wall with irregular, reticulate fissures delimiting polygonal areas. Photobiont trentepohlioid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: thallus without lichen substances; yellow pruina with vulpinic acid.
Note: a cool-temperate, probably holarctic lichen found in dry hollows and undersides, and on the bases of ancient trees, especially oaks, in humid deciduous forests. It is included in the Italian red list of epiphytic lichens as “Near-threatened” (Nascimbene & al. 2013c).