Distribution: N - Frl, Ven, TAA (Nascimbene & al. 2007b, 2014, Nascimbene 2014), Piem (Morisi & Sereno 1995), Emil (Fariselli & al. 2020). C - Marc (Frati & Brunialti 2006), Abr (Nimis & Tretiach 1999, Caporale & al. 2016). S - Bas (Ravera & al. 2015d).
Description: Thallus crustose, of scattered to crowded minute areoles or granules, forming small patches to 3.5 mm in diam, typically at the base of small twigs or along cracks in the bark. Areoles flat to slightly convex, rounded to irregular in outline, up to c. 0.25 mm wide. greenish yellow to pale yellow. Apothecia common, lecanorine, 0.15-0.4(-0.6) mm wide, with a deep yellow, flat to convex disc, and a thin, uneven, entire or granular, finally often excluded margin. Epithecium yellow-brown, covered by a granular epipsamma; hymenium colourless, 60-75 µm high; paraphyses simple or sparingly branched in upper part, with slightly swollen, to 3.5 µm wide upper cells hypothecium colourless. Asci 24-32-spored, clavate, with an apical dome which is I+ blue only in the internal, lower part, interrupted in the centre by a a paler blue strip, Candelaria-type. Ascospores 1-celled to 1-septate, hyaline, oblong to ovoid, 7-12 x 4-5 µm. Photobiont chlorococcoid. Spot tests: thallus and apothecia K- or K+ reddish-orange, C-, KC-, P-. Chemistry: pulvinic acid derivatives.
Note: a cool-temperate, perhaps holarctic lichen of smooth bark, especially of Alnus; overlooked, or confused with similar species, but certainly not common. It is included in the Italian red list of epiphytic lichens as “Data Deficient” (Nascimbene & al. 2013c).