Description: This crustose species is characteristic of old, damp woodlands where it occurs on the mossy trunks of ash, willow and oak. It is frequently sterile (without discs) appearing as a thick, blue-green crust (greyer when dry) the surface becoming granular-sorediate. Naming it in the field can often have lichenologists scratching their heads. When discs are present the naming process is simplified, as these are seen to be jet black with a pale margin. It Ireland it occurs mainly in the west and north.

Key Identification Features:

• When sterile, the Pd+ red and K+ yellow reactions help to confirm it, however to the practised eye, it is the characteristic colour and habitat that are diagnostic
• A species of damp woodland, often growing on trees lining streams or river courses.

Original text submitted by Simon Davey

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

iNaturalist: Megalaria pulverea at iNaturalist World Species Observations database.