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Xanthoria parietina: Common Orange Lichen

Xanthoria parietina, also known as common orange lichen, yellow scale, maritime sunburst lichen, orange lichen, and orange wall lichen, is a foliose (leafy) lichen with a wide distribution.

Considerations for Pets

• Lichens, including Xanthoria parietina, often grow on rocks, concrete, and trees. If pets ingest these materials, there might be other concerns besides the lichen itself.

Considerations for Children

• Lichens are sometimes found on tombstones.
• The pigments of orange lichens can be extracted by boiling to dye wool and other fibers.

Taxonomy and Nomenclature

• Scientific Name: Xanthoria parietina
• Family: Teloschistaceae
• Genus: Xanthoria
• Common Names: Common orange lichen, yellow scale, maritime sunburst lichen, orange lichen, orange wall lichen, sunburst lichen

Distribution and Habitat

• Xanthoria parietina has a wide distribution.
• It grows on rocks, concrete, and trees.
• Often found near cattle farms as it favors ammonia-rich environments.
• Common on coastal rocks in New Zealand as Xanthoria ligulata.

Morphology and Growth Habits

• Foliose (leafy) lichen forming large, rounded patches up to 10 cm across.
• Wide, round-lipped marginal lobes.
• Thallus is yellowish-green to orange, grey in shade.
• Lacks isidia or soredia; apothecia usually present.
• Starts as a small yellow or orange dot, gradually grows, leaving the center white-grey.

Ecological Role

• Grows prolifically in seabird colonies, possibly due to nutrient enrichment.
• Can be found in an orange lichen belt below white and grey lichens.

Interactions with Other Organisms

• Lichens are a symbiotic association between a fungus and an alga. The alga is contained within the hyphae.
• Orange lichens may identify hunting perches of birds.

Quirky Facts

• The orange color of this lichen is due to the production of the pigment parietin.
• Parietin, found in lichens and rhubarb, may have potential as an anti-cancer drug.

Further Information

• British Plant Life 3. National Museum of Wales. Orange, A. 1998.