Description: Short, bare, calcareous turf, soily crevices in limestone, and cliffs with blown shell-sand are all target habitats for T. sedifolia. The rather grey-brown, lumpy-crooked scales (3mm diam.) surmounted by black, dinner-plate shaped discs with a thin, black rim, often develop a faint, shimmering, bluish tinge that is rather alluring, making the species easy to spot in the field. The discs can develop to about the same size as the scales but contrast well with them as they resemble sucked fruit gums — the black ones. These appear frosted over with pruina when young. Throughout Ireland; rare in the east.

Key Identification Features:

• Thallus: two-tone grey to pale brown, lumpy, irregular-shaped scales with a faint, bluish sheen
• Large (to 3mm diam.), black, flat or angular discs, pruinose when young; crevices in limestone rocks.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Thalloidima sedifolium at iNaturalist World Species Observations database.