Nytt Mag. Natur. 7: 232 (1853) [1852].
Basionym: Lichen scruposus Schreb., Spic. fl. lips. (Lipsiae): 133 (1771).
Thallus: crustose, pale to dark grey, often with a yellowish or yellow-green tinge when in shaded habitats, more or less continuous to coarsely cracked-areolate, the surface more or less uneven to verrucose, not pruinose. Apothecia urceolate, 1 - 1.5 - 3 mm in diameter, disc more or less pruinose, thalline exciple more or less raised above the thallus, hymenium 90 - 125 µm tall, hypothecium dark brown to black. Asci 90 - 110 /20 - 25 µm, (4) - 8-spored. Ascospores 20 - 22 - 40 / 10 - 18 µm with 4 - 5 - 7-transverse and 1 - 2 - 3 longitudinal septa. Pycnidia crateriform, conidia bacilliform, 4 - 6 /1 µm (Hawksworth 1992: 237).
Photobiont: Green alga.
Chemistry: Thallus Pd-, K- ord yellow, C+ red, UV - .
Ecology: On silicious or somewhat basic rocks and walls, often in nutrient-enriched sites; frequent (Hawksworth 1992: 237).
Molecular data: Genbank
Distribution: Database
Note:
Race I: Diploschistesic acid, lecanoric acid.
Race II: Lecanoric acid.
Both chemical races occur in Great Britain (Hawksworth 1992: 237).