Description: One of the largest of the ‘pin-head lichen’ tribe, C. viride is known by its thick, bright green, scurfy-granular thallus. The discs (heads – in Calicium speak) sit at the end of black stalks (pins). These can be up to 2mm high with a distinct brown, lower-surface colouring. It grows on the dry, acid bark of trees in woodland, oak especially. It is pollution tolerant. Frequent in the east of Ireland.

Key Identification Features:

• Tall pins to 2mm high, heads brown below
• Thallus bright-green, granular.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Calicium viride at iNaturalist World Species Observations database.