Description: Thallus crustose to more commonly leprose, usually well-developed, thick, yellowish green, consisting of a thick mat of soredia-like granules. Apothecia rather frequent, on long stalks, pin-like, 1.6-3 m tall. Capitulum, maezedium and at least upper part of stalk covered in a dense yellowish green pruina. Asci formed in chains, disintegrating early, producing a mass of spores (maezedium) which accumulates on the surface of the apothecia. Ascospores 1-celled, pigmented, globose, with a very minute, verrucose ornamentation, 2.3-3 µm in diam. Photobiont chlorococcoid, with elongated cells arranged in chains (Stichococcus). Conidiomata hyphomycetous, of dispersed, more or less erect, colourless macronematous conidiophores. Conidia ellipsoid, hyaline, simple, arranged in chains. Spot tests: thallus K-, C-, KC-, P-. Chemistry: vulpinic and pulvinic acids, pulvinic dilactone.
Note: a widespread holarctic lichen found beneath overhanging faces protected from rain, especially in forests, often on exposed roots but rather indifferent to the substrata (also found on siliceous rocks and lignum); in the Mediterranean belt it is restricted to very humid forests.