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Xanthoria parietina: Common Orange Lichen

Xanthoria parietina, a foliose (leafy) lichen, is known by several common names, including common orange lichen, yellow scale, maritime sunburst lichen, orange lichen, and orange wall lichen.

Taxonomy and Nomenclature

• Scientific Name: Xanthoria parietina
• Family: Teloschistaceae
• Genus: Xanthoria

Considerations for Pets

• Grows on rocks, concrete, and trees.

Considerations for Children

• Pigments can be extracted and used to dye wool and other fibers.

Distribution and Habitat

• This lichen has a wide distribution and is often found on rocks, concrete, and trees.
• It is especially prolific near cattle farms due to its preference for ammonia.
• Common on coastal rocks in New Zealand.

Morphological Characteristics

• Xanthoria parietina is a foliose lichen that forms large, rounded patches up to 10 cm across.
• It features wide, round-lipped marginal lobes.
• The thallus color ranges from yellowish-green to golden-yellow or orange, and it may appear grey in shaded conditions.
• It lacks isidia or soredia (asexual reproductive structures).
• Apothecia (fruiting bodies) are usually present, featuring a dark orange disc surrounded by a lighter edge.

Quirky Facts

• The orange color of this lichen is due to the production of the pigment parietin.
• Orange lichens may grow in profusion in seabird colonies and also identify hunting perches of birds.
• The pigment parietin found in this lichen and rhubarb may have potential as an anti-cancer drug.

Interactions with Other Organisms

• Lichens are formed from a symbiotic association between a fungus and an alga.
• The alga Trentepohlia can be seen as a vivid orange powdery deposit on trees.