Description: This species which is well distributed in Ireland grows on the thallus of Thelotrema lepidinum and T. macrosporum. It does not invade T. petractoides. The ascus cells contain eight, three-septate spores, 17µm or less in length.

Key Identification Features:

• A lichenicolous lichen of Thelotrema lepidinum and T. macrosporum
• Spores eight/ascus, three-septate; outer part of slit-like disc K+ greenish.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Opegrapha thelotrematis at iNaturalist World Species Observations database.