SafePlants

Xanthoria parietina: The Common Orange Lichen

Xanthoria parietina is a captivating foliose lichen known for its vibrant color and widespread presence. Often found adorning rocks, trees, and even man-made structures, this lichen adds a splash of color to diverse environments.

Considerations for Pets

• This lichen is known to grow on rocks and trees, including near cattle farms, indicating a potential presence in outdoor environments accessible to pets.

Considerations for Children

• Xanthoria parietina is mentioned as being used to dye wool and other fibers, implying that it contains pigments that can be extracted through boiling.

Taxonomy and Nomenclature

• Scientific Name: Xanthoria parietina
• Common Names: Common orange lichen, yellow scale, maritime sunburst lichen, orange lichen, orange wall lichen, sunburst lichen, golden shield lichen, shore lichen.
• Family: Teloschistaceae
• Xanthoria is a genus of lichenized fungi.
• Synonym: *Xanthoria elegans* (commonly known as the elegant sunburst lichen), Caloplaca Th. Fr.

Distribution and Habitat

• Xanthoria parietina has a wide distribution, occurring on rocks, concrete, and trees.
• It is found near cattle farms, as it favors ammonia.
• It's found in coastal areas, such as the coast of New Zealand, and Humboldt Lagoons State Park, California.
• Also seen in the Western Isles, Triabunna (East Coast Cruises), mountainous areas and on Stanpit.

Morphological Characteristics

• Xanthoria parietina is a foliose lichen, meaning it has a leafy structure.
• It forms large, rounded patches that can grow up to 10 cm across.
• The thallus (body) is yellowish green to orange, sometimes appearing grey in shaded conditions.
• It lacks isidia or soredia.
• Apothecia (fruiting bodies) are usually present, with a dark orange disc surrounded by a lighter edge.

Ecological Role

• Orange lichens can identify hunting perches of birds and grow in profusion in seabird colonies.

Quirky Facts

• The vibrant orange color of Xanthoria parietina is due to the production of the pigment parietin.
• The orange pigment parietin found in lichens and rhubarb may have potential as an anti-cancer drug.
• Lichens are described as "dual organisms" because they are a symbiotic association between a fungus and an alga.
• The alga Trentepohlia can be seen as a vivid orange powdery deposit on tree trunks.

Interactions with Other Organisms

• Lichens are formed from the symbiotic association between a fungus and an alga. The alga is contained within the hyphae.

Further Information

• For the use of chemicals and appropriate precautions and procedures, refer to "Microchemical Methods for the Identification of Lichens" by Alan Orange.