Thallus crustose formed by neighboring angular areoles very tightly packed together, gray-greenish, dirty greyish-green, dirty yellowish-green, gray-blackish hypothallus sometimes present in case of species in contact. Apothecia first submerged in the areoles of the thallus (1-3) little open and more or less angular, only a few becoming sessile, thalline margin protruding, whitish, disc blackish. Asci with (2) 4 (6) spores. Simple, colorless, broadly elliptical spores, 20-30 x 15-25 µm. No colored chemical reactions. Rare taxon, slightly nitrophilic, occurring on damp limestone rocks and in the shade, more rarely on cement or concrete.
_ Watch out for: Circinaria (Aspicilia) leprosescens species with slightly similar colorations but whose thallus is covered with schizidia, the apothecia never sessile and which is strictly coastal on acid rocks.
