Description: The granular thallus of this ‘pin-head lichen’ forms yellow to rusty-red patches on trees which is unmistakable once seen. The colonies can spread like a rash on dry, acid-barked trees and de-barked wood often close to areas with some residual air pollution. The stalked discs (not always present) carry a pale brown spore mass often with a hint of yellow. North and east Ireland.

Key Identification Features:

• ‘Pin-head lichen’ conspicuous as yellow to rusty-red patches on dry, acid-barked trees
• Often on trees in or near air pollution recovery zones close to towns.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Chaenotheca ferruginea at iNaturalist World Species Observations database.