Description: This lichen is common on acid-barked trees, rocks, wood and soil where the effect of nutrient enrichment is generally absent. The thallus consists of a spreading crust of tiny, olive green warts named goniocysts. It is frequently with discs, but these are mostly very small. They vary from pinkish-beige, through darker-brown to black. A beginner may be tricked into believing this is an algal crust. Trees that should be examined for it include alder and birch, especially in the more remote areas of Ireland.

Key Identification Features:

• The scurfy, rather dark, grey to olive green, granule-woven thallus with small discs of a variety of colours generally indicates this species
• It is now known to be a member of an aggregate and separation into the various species of the aggregate is a task for experts.

Original text submitted by Simon Davey

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

iNaturalist: Micarea prasina s. lat. at iNaturalist World Species Observations database.