Description: This light-grey crustose lichen with a thallus of convex granules (0.25mm diam.) is a common species of peaty habitats, acid soils, dry stone walls and rocks especially in upland districts. The discs are rounded and rather shiny blue-black to black. It is abundant in suitable habitats throughout Ireland.

Key Identification Features:

• Where siliceous rocks occur, look out for this species. The bubbly thallus of convex granules stiffening into a crust and almost black, convex discs should distinguish it
• This species occurs in two varieties, distinguishable using chemical tests. The var. lignaria reacts negatively with a dab of fresh bleach [known as (C) in lichenology circles], whereas the var. endoleuca turns yellow-orange.

Original text submitted by Simon Davey

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

iNaturalist: Micarea lignaria at iNaturalist World Species Observations database.