SafePlants

Xanthoria parietina: Common Orange Lichen

Xanthoria parietina, a vibrant and widespread lichen, is known by several common names, reflecting its distinctive appearance and habitats.

Considerations for Pets

• Lichens, including Xanthoria parietina, can grow on rocks, concrete, and trees, sometimes near areas where animals such as those on cattle farms may roam due to the lichens' preference for ammonia.

Considerations for Children

• The pigments of colorful lichens, like the orange hues of Xanthoria parietina, can be extracted by boiling and used to dye wool and other fibers.

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
• Genus: Xanthoria
• Family: Teloschistaceae
• Also mentioned: Xanthoria elegans (Elegant Sunburst Lichen), Xanthoria polycarpa (Pincushion Orange Lichen), Xanthoria ligulata

Distribution and Habitat

• Xanthoria parietina has a wide distribution and can be found in various locations:
• On rocks, concrete, and trees.
• Near cattle farms due to its preference for ammonia.
• Coastal rocks (New Zealand).
• Observed in the Western Isles, covering rocks, ground, and trees.
• Humboldt Lagoons State Park, California, on rocks at the beach.

Morphological Characteristics

• Xanthoria parietina is a foliose (leafy) lichen, forming large, rounded patches up to 10 cm across.
• It has wide, round-lipped marginal lobes.
• The thallus (lichen body) ranges from yellowish-green to golden-yellow or orange, and can appear 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

• Xanthoria parietina can be especially prolific in certain environments.
• The elegant sunburst lichen (Xanthoria elegans) is highly tolerant.
• Orange lichens often identify hunting perches of birds and grow in profusion in seabird colonies.
• The lichen can survive harsh weather conditions due to the symbiotic association between a fungus and an alga.
• It can grow in an area above the salt lichen, usually.

Quirky Facts

• The orange color of Xanthoria parietina is due to the production of the pigment parietin.
• Parietin, found in this lichen, 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 is contained within the hyphae.

Further Information

• Orange, A. 1994. Lichens on Trees. A Guide to Some of the Commonest Species. Series: British Plant Life 3. National Museum of Wales.
• Orange, A. 1998. Microchemical Methods for the Identification of Lichens by Alan Orange.