Click on map to open large map in new window
(Map updated: 11 August 2009)

In country with hard, calcareous rock outcrops this grey-white, crustose lichen will be a principal species. The small, brown-black, often grey-frosted discs (0.3-0.5mm) lie in pits level with the rock surface. Close to the rock its beauty should unfold for often the first inklings of its presence are the grey, evenly scattered, frosted discs. It occurs mostly on well-illuminated limestones but can also be found among the more sheltered rocks. Throughout Ireland.

Key characteristics

• Thallus whitish, with blackish, grey-frosted discs in pits in the stone (rather like the dots on a distribution map)
• On hard limestone surfaces, for example, limestone pavements, ledges, etc., sometimes in churchyards.

Original text submitted by Vince J. Giavarini