Description: Thallus crustose-subsquamulose, bright yellow to greenish yellow in shade-forms, of minute, 0.2-0.8(-1) mm wide, scattered to mostly contiguous, flattened, ireegularly lobulate squamules which may cover large surfaces on the trunks. Central parts of squamules soon giving rise to yellow, finely granular (0.05-0.07 mm diam.) soredia which usually entirely cover the upper surface, giving the thallus a subleprose appearance. Apothecia very rare, 0.5-1 mm across, yellow, with a flat to convex disc and a thin, smooth to sorediate margin. Epithecium yellowish; hymenium and hypothecium colourless; paraphyses cylindrical, parallel, some of them branched in upper part. Asci 8-spored, clavate, Candelaria-type. Ascospores 1-celled, hyaline, ellipsoid, sometimes slightly curved, 10-17 x 4.5-5.5 µm. Pycnidia immersed in the squamules, the wall colourless. Conidia oblong to ellipsoid, c. 3 x 1.5 µm. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-. Chemistry: pulvinic acid derivatives.
Note: a mild-temperate, holarctic lichen found on isolated trees, especially along waysides and in agricultural areas, somehow rarer along the Adriatic side of the Peninsula, and rare throughout Mediterranean Italy, very common elsewhere in the submediterranean belt.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)