Description: While now presumed extinct in Ireland (last seen in the nineteenth century in Connemara, County Galway), Arctomia delicatula should be looked for growing on bryophytes and on the thallus of Polychidium muscicola both on trees such as birch, hazel and willow, and on mossy rocks especially in the north and west of Ireland. The thallus is minutely granular to squamulose (scale-like), sometimes barely visible when on Polychidium. The discs are dark red-brown, convex; spores are colourless 7- to 10-septate.

Key Identification Features:

• Forms a tiny, gauzy thallus over bryophytes on damp tree surfaces or mossy rocks; also parasitizes Polychidium muscicola
• Discs (to 0.5mm diam.), red-brown, convex.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Arctomia delicatula at iNaturalist World Species Observations database.