Description: Rare in Ireland, this tiny lichen resembles C. lenticularis but with lower, flatter discs. It is recorded from dry, well-lit limestones in County Clare, from Rathlin Island and from mainland County Antrim but should be more diligently looked for among calcareous screes below cliffs as well as on their vertical faces, for example, similar to the habitat it occupies in Britain. The small, discs (0.2-0.5mm diam.), convex at maturity, vary from dark brown to black.

Key Identification Features:

• Small, convex, brown-black discs with one-septate spores
• On calcareous, vertical cliff faces and screes.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Catillaria aphana at iNaturalist World Species Observations database.