SafePlants

Xanthoria parietina: The Common Orange Lichen

Xanthoria parietina, a striking foliose lichen, is widely recognized for its vibrant color and broad distribution. This lichen, often found adorning rocks, trees, and even tombstones, contributes to the diverse tapestry of ecological communities around the world.

Common Names

• Common orange lichen
• Yellow scale
• Maritime sunburst lichen
• Orange lichen
• Orange wall lichen
• Sunburst lichen
• Golden shield lichen
• Shore lichen

Taxonomy and Nomenclature

• Genus: Xanthoria
• Family: Teloschistaceae
• Xanthoria elegans is mentioned as another species.
• Caloplaca luteoalba and Caloplaca microphyllina are also referenced, though are distinct species.

Considerations for Pets

• This lichen often grows on rocks, concrete and trees, sometimes near cattle farms and may be encountered during outdoor activities.

Considerations for Children

• This lichen often grows on rocks, concrete and trees, sometimes near cattle farms and may be encountered during outdoor activities.

Distribution and Habitat

• Xanthoria parietina has a wide distribution and is found in various locations, including coastal rocks, mountainous areas, and even tombstones.
• It grows on rocks, concrete, and trees and can be found near cattle farms, indicating a preference for ammonia-rich environments.
• Observed in places such as the Western Isles, New Zealand, Mount Washburn Trail (Yellowstone National Park, Wyoming) and Humboldt Lagoons State Park, California.

Morphological Characteristics

• Xanthoria parietina is a foliose lichen, forming large, rounded patches up to 10 cm across.
• The thallus (body) is yellowish-green to orange, sometimes appearing grey in shaded conditions.
• It lacks isidia or soredia and typically features apothecia (fruiting bodies).
• Some related lichens have a crust-like texture.

Ecological Role

• Lichens can survive harsh weather conditions that would kill a fungus or alga growing separately due to their symbiotic relationship.
• The presence of orange lichens can identify hunting perches of birds.
• Lichens favor rough, water-retentive, naturally alkaline bark.

Interactions with Other Organisms

• Lichens are a symbiotic association between a fungus and an alga.
• Orange lichens often grow in profusion in seabird colonies.

Quirky Facts

• The orange color of Xanthoria parietina is due to the production of the pigment parietin.
• Pigments from colorful lichens, including orange ones, can be extracted and used to dye wool and other fibers.
• One source indicates that orange lichen is a sign of a healthy forest.

Parietin

• Parietin is an orange pigment found in lichens and rhubarb.
• It is being studied for its potential as an anti-cancer drug due to its interference with cancer cell metabolism.

Further Information

• Microchemical Methods for the Identification of Lichens by Alan Orange is referenced as a useful resource.