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Arctoparmelia

Arctoparmelia is a genus of lichens within the family Parmeliaceae.

Taxonomy and Nomenclature:

• Scientific Name: Arctoparmelia Hale, 1986
• Family: Parmeliaceae

Synonyms:

• Arctoparmelia aleuritica (Nyl.) Hale
• Parmelia aleuritica Nyl.
• Parmelia centrifuga (L.) Ach.
• Xanthoparmelia centrifuga (L.)

Common Names:

• Arctoparmelia lichen
• Powdered rockfrog lichen (for Arctoparmelia incurva)
• Concentric-ring Lichen
• Ripple Ring Lichen
• Target Lichen

Morphological Characteristics:

• Thallus is foliose and closely adnate to the substratum.
• Commonly dies in the center, forming concentric rings.
• Lobes are irregularly branching with pointed, flat tips.
• Color ranges from yellow to yellow-grey.
• Lobes are narrow, crowded, radiating, and convex in cross-section.
• Lobe tips are often turned under, with a pale brown underside.

Distribution and Habitat:

• Common on rocks and boulders.
• Found in various locations, including Newfoundland (Annieopsquotch Mountains), Quebec (Parc Laurentides, Canada), Northwest Territories (Yellowknife, Canada), West Greenland (Kangerlussuaq area), and Alaska (Serpentine Hot Springs, Bering Land Bridge).
• Often found in taiga (Scotch Pine) forests.

Ecological Role:

• Saxicolous, meaning it grows on rocks, and is subjected to desiccation stress and intense light levels.
• Decreasing in Sweden, as dead pines and unpainted hay barns become rarer.

Quirky Facts:

• The concentric ring pattern is formed as the interior of the lichen dies back and is recolonized.

Further Information:

• Referenced in "Lichens of North America" by Brodo, I.M., Sharnoff, S.D. and Sharnoff, S. (2001).
• Photographs and information available at Getty Images.