Description: This lichenicolous species (thallus K+ yellow to red) usually occurs as warts on the thallus of Lecidea lapicida. It forms white, convex, gall-like nodules with black discs peppering the surface, like spots on a ladybird. Close attention to the discs will show they have a plug of tissue (an umbo) at the centre. In Ireland, it is known from Counties Kerry (south), Sligo and Londonderry.

Key Identification Features:

• Wart-like on Lecidea lapicida, thallus white, K+ yellow-red
• Discs black, with an umbo developing at maturity.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Cecidonia umbonella at iNaturalist World Species Observations database.