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(Map updated: 11 August 2009)

Grey to green-grey ‘powder lichen’ of damp, acid habitats and shaded niches such as hollows in tree bark, holes in earth banks, trees in coniferous plantations and rock underhangs. Often appears blue-green to the naked eye. Scratching with a fingernail can remove the scurfy granules. There should be no suggestion of a cotton-white layer within (medulla). In deep shade it can form a thick, powdery crust. It never produces fruiting discs.

Key characteristics

• Powdery crust with blue-green appearance lacking a white, fluffy, cotton-wool-like underlayer
• On scratching, the powdery granules will detach instantly.

Original text submitted by Vince J. Giavarini