Description: This crustose epiphyte forms small, grey, circular patches dusted with little heaps of yellow-green powdery soralia. Its favourite host is sallow, so can be easily searched for in willow swamp. It occurs on the main stems of trees as well as branches and twigs (often together with the slightly less common Japewiella tavaresiana). Discs are uncommon, but when present consist of olive-coloured fruits mixed in with the soralia. Suitable habitats throughout Ireland include field edges, flooded woods, ponded pastures, bogs and river corridors. It is probably one of Ireland’s most characteristic species.

Key Identification Features:

• The pale grey thallus, evenly scattered yellow-green soralia (powder) and preference for willow should easily distinguish it from other species
• Similar powdery sorediate species such as Lecanora expallens do not have evenly scattered soralia or the same coloured thallus.

Original text submitted by Simon Davey

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

iNaturalist: Lecanora jamesii at iNaturalist World Species Observations database.