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Xanthoria parietina: Common Orange Lichen

Xanthoria parietina, a foliose lichen, is known by several common names, including common orange lichen, yellow scale, maritime sunburst lichen, and orange wall lichen. It is often found as splashes of orange on various surfaces.

Considerations for Pets

• Lichens can grow on rocks, concrete, and trees.
• They are often found near cattle farms due to their preference for ammonia-rich environments.
• Lichens can be found on tombstones.

Taxonomy and Nomenclature

• Scientific Name: Xanthoria parietina
• Family: Teloschistaceae
• Other species in the genus Xanthoria include Xanthoria elegans and Xanthoria polycarpa.
• Caloplaca is another genus in the same family, Teloschistaceae

Distribution and Habitat

• Xanthoria parietina has a wide distribution and can be found in various locations.
• It is commonly found on rocks, concrete, and trees.
• Frequently observed in coastal environments and mountainous areas.
• Also found in New Zealand, covering all types of land from coast to mountain.

Morphological Characteristics

• Foliose (leafy) lichen forming large, rounded patches up to 10 cm across.
• It exhibits wide, round-lipped marginal lobes.
• The thallus (body) color ranges from yellowish-green to golden-yellow or orange, and may appear grey in shaded conditions.
• It lacks isidia or soredia (reproductive structures).
• Apothecia (fruiting bodies) are usually present, featuring a dark orange disc surrounded by a lighter edge.
• When young, it starts as a small yellow or orange dot and gradually grows outward.

Ecological Role

• This lichen can survive harsh weather conditions due to the symbiotic relationship between a fungus and an alga.
• Orange lichens may identify hunting perches of birds.

Quirky Facts

• Pigments from colorful lichens, including Xanthoria parietina, can be extracted by boiling and used to dye wool and other fibers.
• The orange color of Xanthoria parietina is due to the production of the pigment parietin.
• Parietin may have potential as an anti-cancer drug.

Interactions with Other Organisms

• Lichens represent a symbiotic association between a fungus and an alga.
• The alga Trentepohlia can be seen as a vivid orange powdery deposit.

Further Information

• Microchemical Methods for the Identification of Lichens by Alan Orange.
• Lichens on Trees. A Guide to Some of the Commonest Species, by A. Orange.