Description: This crustose species was once widespread on trees in our polluted towns and cities. It thrives in S0₂-rich atmospheres. Following the campaign for cleaner air, it has suffered dramatic decline. It now occurs typically on worked timber, for example, wooden posts. It also occurs on pine twigs and on the stems of heather as well as occasionally on acid rocks, especially in still-polluted areas. It is a rather grubby species with a thick granular-sorediate thallus. The small (to just over 1mm diam.), flesh-coloured discs have sorediate margins. The thallus is Pd + yellow to rust red. It has an easterly distribution in Ireland probably because in the high rainfall areas of the west there is more competition from other species.

Key Identification Features:

• It shares with Lecanora confusa beige to greenish fruits scattered on a scurfy, beige-coloured thallus. It is immediately from that species by the instant reaction with Pd turning from yellow rapidly to rust red
• With cleaner air predominating, L. conizaeoides is becoming rarer to find.

Original text submitted by Simon Davey

Distribution Map from NBN: Lecanora conizaeoides f. conizaeoides at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Lecanora conizaeoides f. conizaeoides at iNaturalist World Species Observations database.