Epilichen scabrosus  

Thallus crustose, often in quite small patches, areolate to subsquamulose, yellow to yellowish-green or pale green, often appearing swollen, sometimes reduced when parasitizing other lichens, at least sometimes without a distinct cortex. Prothallus absent. Photobiont unidentified coccoid green algae.
Anamorph: not known.
Teleomorph: ascomata apothecia, 0.2-0.8 mm diam., arising on the areoles, black, becoming convex, not pruinose, sometimes coalescing. True exciple brownish black, inconspicuous, thalline exciple absent. Hypothecium thick, dark brown (but paler than the exciple). Hymenium 70-100 μm tall, colourless to greenish, K-, K/I+ blue. Interascal tissue composed of thin-walled frequently branching and anastomosing paraphyses 2-3 µm in diam. immersed in a K/I+ blue gelatinous matrix, the apical cells slightly inflated, within a dark olivaceous to brown epithecium. Asci 50-70 × 14-17 μm, cylindric-clavate, the apex of the tholus K/I+ blue, 8-spored. Ascospores arranged irregularly,  (10-)11.5-14(-18) × (4-)5.5-7.5(-9.5) μm, ellipsoidal, rounded or occasionally broadly apiculate at the ends, initially grey to olivaceous and maturing dark brown, 1-septate, smooth, thick-walled, the slightly constricted central septum thickened with an internal torus, lacking a distinct perispore.
Chemistry: thallus C–, K–, Pd+ yellow-orange, UV+ orange (unidentified pulvinic acid derivatives).