Description: Most past records of C. polycarpa in Ireland belong here owing to the mistakenly held belief that C. polycarpa was a parasite of Verrucaria spp., especially V. baldensis. C. oasis is the correct name for the Verrucaria parasite but it can also grow independently on calcareous man-made substrates such as concrete and mortar. Well-developed forms are also those which are parasitic. In Ireland, the species is widely distributed; it is not uncommon.

Key Identification Features:

• Often parasitic on V. baldensis on limestone buildings and churchyard monuments
• A member of the C. holocarpa group; discs small 0.2–0.4mm diam.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Flavoplaca oasis at iNaturalist World Species Observations database.