Gardd Fotaneg Genedlaethol CymruNational Botanic Garden of WalesNational Botanic Garden of Wales

Yellow Wall Lichen

Xanthoria parietina

Its yellow colour stands out on cold winter days

Although most lichens are shades of greenish or bluish grey, others are white, brown, black, reddish – even bright yellow or orange. These colours are caused by chemicals, often acids, produced by the fungal partner.

The bright orange yellow wall lichen Xanthoria parietina is a common, easily recognised lichen especially in nutrient-enriched sites. Look for it on trees and on many of the boulders in the Rock of Ages, where it benefits from the nutrient-rich droppings of perching birds.