Description: This crustose bark lichen belongs to a group of finely granular, pastel-coloured pioneer species that can form extensive patches on wayside trees. The group includes Lecanora expallens, Lecanora barkmaniana and Pyrrhospora quernea. Thankfully, they can be separated by differences in thallus colour and by using chemical spot tests. L. compallens is drawn to areas of bark exposed to the worst of the weather. It has a grey warted thallus which slowly dissolves into fine grey soredia. At first the soredia may follow slender cracks in the bark. Scratching the surface with a fingernail will reveal a white medulla (internal layer) which all the above species lack. Spot tests negative. In Ireland, the species occurs in Counties Wexford and Monaghan.

Key Identification Features:

• Grey sorediate thallus with a narrow margin; medulla white
• Exposed tree bark; waysides often young stand-alone trees; spot tests negative.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lecanora compallens at iNaturalist World Species Observations database.