Description: This soil-loving species forms delicate, pale olive green to green-brown patches in mossy limestone crevices, including the tiny spaces between rock fragments on tracks and paths. Essentially, the thallus is composed of plump, uneven (or frilly-edged) wrap-around scales (squamules) to 2mm diam. which cluster together forming small mounds only a centimetre or so wide. The discs embedded in the squamules are visible as small black dots. It grows to the size of a cushion moss, often intermixed with Collema or Leptogium species. In Ireland, the lichen is known from Counties Galway and Sligo.

Key Identification Features:

• Tiny pale, olive green squamules: heaped and interlocked with discs visible as black dots on the surface
• Among mosses on compacted lime-rich soils.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Placidiopsis custnani at iNaturalist World Species Observations database.