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

This is a ‘powder-lichen’ of hard calcareous rocks. It grows towards the base of cliffs and boulders and in caves and underhangs sheltered from direct sunlight and rain. The white or pale-grey thallus has a weakly-lobed margin and cottony centre. Reactions: C-, PD+ orange. Most Irish records of L. crassissima belong here. Western Ireland; scattered elsewhere.

Key characteristics

• White thallus with weakly-lobed margin; PD+ orange
• Sheltered cliff underhangs, undersides of large, limestone boulders etc.; rarely on acid rock.

Original text submitted by Vince J. Giavarini