Xanthoria polycarpa
The thallus of this small foliose lichen has finely divided greyish-yellow finger like lobes about 1 mm wide, which are often obscured by the yellow-orange apothecia which can cover the entire thallus. The apothecia are up to 4 mm wide, with short stalks and raised greyish-yellow margins. They become contorted with age.
Chemistry: Thallus K+ crimson/purple.
Similar species: Xanthoria parientina has broad lobes. Xanthoria aureola is coastal with narrow strap-like lobes. Caloplaca species are K+ crimson/purple but are crustose.
See also Fungi of Great Britain and Ireland
Common on young twigs and also on dead wood and rocks in areas where nitrogen deposition is high.
Widespread in lowland agricultural areas, but not as common as the map suggests.
Text by Pat Wolseley