Order: Arthoniales       Family: Roccellaceae Species: Opegrapha calcarea Growth type crustose, graphid. Photos: On estuary wall. Creagh, Cork, SW Ireland. Pinkish immersed thallus with black, unbranched lirellae, 1mm. Lirellae variable, can be star-shaped, slit-like or form piled heaps. Occurs on shaded calcareous or basic rocks and on man-made substrates. Also on shaded basic to acidic coastal rocks. Thallus: chemical reactions negative. Opegrapha calcarea includes O.conferta, O.chevallieri, O.saxatalis and other former species.

     



Opegrapha calcarea on coastal rock, Creagh, County Cork. February 2009