• Placidiopsis custnani (A.Massal.) Müll.Arg.
Placidiopsis custnani
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(Map updated: 11 August 2009)

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 characteristics

  • 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

 Simms, M. J., (2016). Placidiopsis custnani (A.Massal.) Müll.Arg.. [In] LichenIreland. Accessed on 2019-01-16.