Description: The chosen habitat of this species appears to be the horizontal tops and flat edges of limestone monuments and memorials. It always grows at the centre of bland, circular zones (3–6cm diam.) where there appear to be no other competing species – not even the hint of an alien thallus. The thallus of S. gibba is nowhere apparent, except around the foot of the black, spherical discs (perithecia) which appear plump and rather squashed, like supermarket onions with part of the base sliced off. The discs regularly occur in groups of two or three. Hunting for it on the flat tomb tops of a churchyard with a few like-minded colleagues can introduce a competitive edge into the proceedings.

Key Identification Features:

• Thallus hidden in the rock; discs in small groups at thallus centre, black, squat, like water-filled onions
• Spores: dumb-bell shaped; limestone tomb-tops – usually towards the edges.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Sarcopyrenia geisleri at iNaturalist World Species Observations database.