Description: Known from several counties at opposite ends of Ireland, L. caesiosora is an occasional sorediate crustose lichen of acid rocks and large, firmly grounded boulders, especially on vertically orientated surfaces. Rarely with discs, the white-grey, K+ yellow thallus of convex areoles (occasionally accompanied by dark brown granules), and clumps of paler soredia, is usually sufficient to distinguish it.

Key Identification Features:

• Thallus white-grey of convex areoles, K+ yellow
• Soredia paler than the thallus, first in clumps, then coalescing and spreading.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lecanora caesiosora at iNaturalist World Species Observations database.