WildBristol.uk - Discovering Wildlife in Bristol

Common and widespread throughout the UK. Habitat includes: Nutrient enriched places on rocks, walls, cement, tiles, tree trunks (often grows where bird droppings land). Highly pollution tolerant. Identification: This lichen is highly variable in colour. It can be yellow, orange or green. The chemical xanthorin (yellow colour) is thought to be produced as a defence against UV radiation. In exposed environments this lichen tends to be more yellow. When it is growing in the shaded, unexposed places it does not require the protection. Xanthorin production stops and the lichen remains green. When wet, this lichen appears more greeny yellow due to the algae showing through the more translucent fungus.