Description: This is primarily a crustose lichen of wood and worked timber. It has something of the appearance of Lecanora jamesii, but the yellow or yellow-white soredia are granular rather than floury and have a distinctive K+ yellow reaction. When fertile, there is never any doubt as L. farinaria has discs with a conspicuous sorediate margin. Lecanora barkmaniana can occasionally present similar characteristics but has a pale grey prothallus, grows in dustier environments and has a disc rim that is UV+ pale orange. In Ireland, the species is known from Counties Fermanagh and Donegal and should be searched for where wooden fence railings are used as boundary markers.

Key Identification Features:

• Thallus granular sorediate, no prothallus and discs with sorediate rims
• On tops of exposed, fast-drying wooden fence rails: estates, parkland landscapes etc.; K+ yellow; UV+ pale orange disc margins.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lecanora farinaria at iNaturalist World Species Observations database.