Description: This dull, pale yellow lichen of siliceous rocks and boulders is an important feature of the lichen flora of upland areas on acid rocks, but occurs so sparingly it is easily missed. Despite the colour the thallus is not obvious from a distance. The surface is cracked and covered with finely powdery, greenish-yellow soralia that frequently coalesce. Discs are rare. It turns orange with a dab of fresh bleach. It occurs in upland and coastal Ireland mainly.

Key Identification Features:

• This is best separated by its dull, yellow colour, habitat of exposed siliceous rocks and large boulders, and the C+ orange spot reaction
• The soralia are characteristically UV+ bright orange.

Original text submitted by Simon Davey

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

iNaturalist: Pertusaria flavicans at iNaturalist World Species Observations database.