Description: Thallus inapparent, growing on the thalli and apothecial margins of Lecanora populicola. Apothecia lecanorine, small, 0.2-0.8 mm across, with a flat to convex, yellow disc and a thin, concolourous, smooth, finally often excluded margin. Thalline exciple prosoplectenchymatous, with protruding hyphae; epithecium yellow; hymenium colourless, 50-60 µm high; paraphyses with slightly swollen tips; hypothecium colourless. Asci 8-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, ellipsoid, hyaline, 16-22 x 5-7 µm. Photobiont chlorococcoid. Spot tests: apothecia K- or K+ reddish-orange, C-, KC-, P-. Chemistry: apothecia with pulvinic acid derivatives.
Note: a cool-temperate lichen starting the life-cycle on Lecanora populicola; overlooked in the past but certainly not common in Italy. It is included in the Italian red list of epiphytic lichens as “Endangered” (Nascimbene & al. 2013c).
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)