Description: Thallus crustose, thinly episubstratic, ochraceous to brown, areolate, becoming completely blastidiate and forming a continuous subleprose crust, the blastidia brown, up to 20-35 µm in diam. Apothecia rare, lecideine, (0.1-)0.2-0.3 mm across, sessile. with an initially urceolate then flat, brownish to black, epruinose disc, and a thin, persistent, reddish brown to black proper margin. Proper exciple paraplectenchymatous, 10-35 µm wide laterallly, expanded to 40(-50) µm in lower part, the outermost part dark brown, of up to 8 µm wide cells with dark brown caps, the inner part pale reddish brown, of 5-6 µm wide cells; epithecium reddish brown to brown; hymenium colourless, (50-)60-70 µm high, not inspersed with oil droplets; paraphyses slender, c. 1 µm thick at mid-level, the apical cells 2-3 µm wide; hypothecium 60-80(-100) mm high, dark brown in upper part, reddish brown in lower part. Asci 8-spored, clavate, Bacidia-type. Ascospores (1-)3-septate, rarely submuriform with a single longitudinal septum in each middle cell, brown, straight or very slightly curved, (14-)15-17.5(-18) x (5-)5.5-7.5(-8.5) µm, smooth-walled, the inner wall thickenings very pronounced at septa and absent at apices, with ontogeny of type A (apical wall thickenings produced after septum formation). Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: an inconspicuous, easily overlooked lichen known from the SW Iberian Peninsula, on Quercus suber; to be looked for in Italy, especially in Sardinia.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)