Family: Stictidaceae Species: Petractis clausa Growth type crustose. Identification confirmed by AJ Silverside Photos: On limestone. Carran turlough, the Burren, Ireland. Thallus is scurfy or endolithic (buried in substrate), whitish-grey to yellowish, often flecked blue-grey. Small, initially immersed apothecia covered with thin layer of cortex which splits revealing pinkish to orange-yellow discs surrounded by white star-like teeth. Found on shaded, +/- damp limestone rocks and pebbles. Chemical reactions negative. Similar: Gyalecta jenensis, also on damp, shaded limestone

Petractis clausa. Carran turlough, the Burren, Co. Clare. April 2009