Description: Look for this silky-suave crustose species in narrow clefts and openings below sheltered siliceous rocks, especially along inland cliffs. It has a thin varnish-like, grey-brown to greenish thallus and attractive elongate discs (spores five- to seven-septate), each a snake-like slit. It is light-intolerant and so is often found in the company of other photophobic taxa such as Enterographa hutchinsiae.

Key Identification Features:

• Shiny, varnish-like thallus in sheltered clefts of siliceous rock outcrops, sometimes mosaic-forming
• Lirellae: attractive, serpent-like; spores 3–5µm wide, five- to seven-septate.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Opegrapha lithyrga at iNaturalist World Species Observations database.