Description: This is a rare lichen of Irish hazel woods in the west. The shiny, silvery-grey thallus spotted with small black discs (perithecia) brings to mind genera such as Arthopyrenia and Anisomeridium. However, the distinguishing feature of this species lies in the configuration of the perithecia which are arranged in lines of two-seven, some occasionally falling out to leave a black-stained pit. Under the microscope the spores are spindle-shaped (fusiform) and many-celled (muriform). It is known in Ireland from Fermanagh and Clare (The Burren).

Key Identification Features:

• Silver-grey thallus; perithecia, singly or in lines of two-seven often stained black where discs fall out
• Spores fusiform and muriform; on thin hazel stems.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Swinscowia tagananae at iNaturalist World Species Observations database.