Description: Thallus crustose to subleprose, bright yellow-green, turning grey-green or brown-green in the herbarium, sorediate, often forming very large patches. Soredia at first gathered into 0.1-0.2 mm wide, discrete and punctiform soralia, but soon covering the whole thallus, forming an up to 1 mm thick, more or less cracked layer of soredia; soredia 30-50 μm in diam. Apothecia rare, sessile, constricted at base, (0.2-)0.4-0.7 mm across, witrh a flat, pale pink to dark blue-black, often only partly coloured disc, the darkened parts with an aeruginose-blue pigment in section; proper margin conspicuous, 0.1-0.2 mm wide, pinkish with aeruginose-blue or dark brown flecks. Proper exciple well-developed, 25–35 μm thick, the cells with isodiametric to slightly ellipsoid lumina, colourless but often aeruginose-blue or orange-brown in upper parts, without crystals; epithecium colourless to aeruginose-blue or orange-brown, 5-10 μm thick, K- or the coloured parts K+ intensifying; hymenium colourless or orange-brown, K+ intensifying brown-purplish, 60-70 μm high; paraphyses c. 1 μm thick at base, the apical cells up to c. 5 μm wide; hypothecium colourless or very pale straw-coloured, 40-60 μm high. Asci 8-spored, cylindrical-clavate, approaching the Bacidia-type, but the ocular chamber wider, and the axial body never penetrating through the entire d-layer, surrounded by a narrow, darker amyloid layer. Ascospores 2-10-septate, hyaline, acicular, straight or slightly curved, 40-50 x 0.9-1.2 μm. Pycnidia rare, white, immersed, c. 0.1 mm across. Conidia thread-like, 35-50 x 1-1.2 μm, with 4-6 indistinct septa. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: recently described from the Netherlands, and known from Belgium, England and Germany (Sparrius and Aptroot, 2003), bound to anthropized environments where it usually grows on acid or neutral, eutrophicated bark.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)