Order: Arthoniales Family: Roccellaceae
Species: Opegrapha gyrocarpa
Photos: On shaded acidic rock. Gougane Barra, Cork, SW Ireland.
Identification confirmed by John Douglass
Thin or finely cracked pale brown to deep reddish-brown thallus, sometimes with pinkish patches. Dark-brown to black prothallus. Yellowish soralia are scattered over the surface giving a flecked appearance. Knot-like or gyrose apothecia are occasional, usually scattered. Can form extensive mosaics.
Occurs on humid, shaded, neutral or siliceous rocks, often in old woodlands or on old dry-stone walls.
Soralia K-, C+ red, KC+ red, P-, UV+ glaucous or pale yellow
Similar: Belonia nidarosiensis. On limestone, mortar, cement. C-
Opegrapha gyrocarpa. August 2009