SafePlants

Xanthoria parietina (Common Orange Lichen)

Xanthoria parietina, commonly known as common orange lichen, is a widely distributed foliose lichen. Its vibrant color makes it easily identifiable in various environments.

Nomenclature and Taxonomy

• 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
• Genus: Xanthoria
• Also mentioned: Xanthoria elegans, Xanthoria polycarpa,

Distribution and Habitat

• Xanthoria parietina has a wide distribution and can be found growing on rocks, concrete, trees, and even tombstones.
• It is often prolific, especially in areas with high ammonia content, such as near cattle farms and seabird colonies.
• Specific locations mentioned include the Western Isles, the Gyon Bluffs near Freshwater Lagoon in Humboldt Lagoons State Park, California, and the East Coast of Triabunna.

Morphological Characteristics

• Xanthoria parietina is a foliose lichen, forming large, rounded patches that can reach up to 10 cm across.
• It has wide, round-lipped marginal lobes.
• The thallus (lichen body) ranges in color from yellowish green to golden-yellow or orange, sometimes appearing grey in shaded areas.
• It lacks isidia or soredia, and apothecia (fruiting bodies) are usually present. These have a dark orange disc surrounded by a lighter edge.
• It starts as a small yellow or orange dot and gradually grows outward, sometimes leaving the center white or grey.

Ecological Role and Interactions

• Orange lichens, including Xanthoria parietina, may indicate hunting perches of birds.
• Lichens, in general, are described as "dual organisms," representing a symbiotic association between a fungus and an alga.
• The alga, contained within the hyphae of the fungus, allows the lichen to survive harsh weather conditions.

Quirky Facts

• The orange color of Xanthoria parietina is due to the production of the pigment parietin.
• This pigment, parietin, which is also found in rhubarb, is being studied for its potential as an anti-cancer drug.

Traditional Uses

• Pigments extracted from colorful lichens, including orange ones, can be used to dye wool and other fibers.

Resources and Further Information

• Katja Schulz has marked "Common orange lichen 3" as trusted on the "Xanthoria parietina" page.
• Caloplaca Th. Fr. database provides general information on the family Teloschistaceae.
• Alan Orange's "Microchemical Methods for the Identification of Lichens" is a resource for chemical identification.
• "Lichens on Trees. A Guide to Some of the Commonest Species" by A. Orange (1994) published by the National Museum of Wales is a helpful guide.