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.
![Key to map date classes](/sites/default/files/default_images/species-maps-key_2.png)
Widespread in lowland agricultural areas, but not as common as the map suggests.
Text by Pat Wolseley