Thallus
Foliose, up to 2-3 cm, sometimes confluent with other thalli, can cover large areas, lobes 0.5-1.5 mm broad, margins with pale cilia, darker at the end
Reproduction
Apothecia: infrequent, 1-2 mm in diameter, disc black and pruinose
Soralia: numerous, greyish, slightly greenish on the edges of the lobes
Isidia: —
Substrate
On bark, sometimes on rock or artificial substrate
Occurrence
Very common, widespread in urban areas
Air pollution
Resistant to pollutants