Order: Arthoniales       Family: Opegraphaceae Species: Opegrapha rupestris Growth type crustose. Parasitic. Photos: Parasitic on Verrucaria. Black Head, the Burren, Ireland. BLS Burren meeting 2009 Thallus barely visible. Scattered clusters of small, +/- rounded lirellae with a persistently narrow central slit. Spores are 3-septate, 14-22 × 5-8 µm, hyaline becoming brown when over-mature Lichenicolous on Bagliettoa baldensis (Verrucaria baldensis) and Bagliettoa calciseda (calciseda) on natural limestone rocks and memorials, but most frequent on Verrucaria baldensis. Recorded from northern and western Ireland.

Opegrapha rupestris. BLS Burren meeting, April 2009