A bright yellow to orange foliose lichen (often grey in the shade). Thallus of large slightly wrinkled overlapping lobes. Underside white. Fruiting bodies numerous especially towards the centre- orange apothecia with paler margin
Chemistry: K+ crimson/purple
Similar species: Xanthoria polycarpa has narrow lobes and numerous stalked apothecia which almost hide the thallus. X. aureola is coastal with narrow strap-like lobes. Caloplaca species are also K+ crimson/purple but are crustose.
See also Fungi of Great Britain and Ireland
Urban, rural and coastal. On nutrient enriched trees (e.g. elder), rocks, walls and roofs, especially if exposed to bird droppings or air pollution.
Widespread, common and increasing due to nitrate and ammonia pollution.
Text by Heather Paul & Sue Knight