Description: This soil-inhabiting lichen has a thallus of reddish-brown, unevenly-shaped, indistinctly dark-edged, non-hairy, scaly squamules (to 7mm across) with colourless or slightly browned attachment organs (rhizohyphae). The black, spherical discs (perithecia) lie buried in the thallus with the tops just showing as tiny, black dots. Open calcareous soils and mortar; also crevices in walls especially near the coast. It is local in Ireland.

Key Identification Features:

• Squamules (large, to 7mm) without a conspicuous darkened or hairy rim
• Attachment organs not dark, some slightly browned only; on lime or lime-mortared walls.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Placidium squamulosum at iNaturalist World Species Observations database.