Description: In appearance the thallus of this species is like L. lapicida (described elsewhere), but in L. plana spot tests are all negative. The consistently pale grey thallus, and discs remaining black when moist, separate it from L. lithophila (thallus with rusty patches). A section through the exciple (disc rim) shows up as yellow-grey. Siliceous rocks, more frequent in Northern Ireland.

Key Identification Features:

• Cracked, consistently grey crustose lichen, thallus K-; discs remaining black when moist, exciple in section yellow-grey
• Siliceous rock; a predominantly northern upland species.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lecidea plana at iNaturalist World Species Observations database.