Stonewall Rim Lichen
(Protoparmeliopsis muralis)
Conservation • Description • Ecology • Distribution • Taxonomy
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Description |
Stonewall Rim Lichen is a widespread, very common lichen. It occurs worldwide on every continent except Antarctica. It is most common in Europe and North America. It grows on rock, specifically basalt, pumice, rhyolite, granite, sandstone, and limestone. It occasionally grows on bark. It is extremely variable, and as currently circumscribed, it is probably a complex of several closely related species. The vegetative body (thallus) is a neat, circular rosette divided into lobes. It is usually ⅝″to 1⅜″ (1.5 to 3.5 cm) in diameter, but it can be larger. It sometimes merges with adjacent thalli, creating what appears to be a large irregular thallus. It may be closely adhered to or loosely attached to the substrate. It is either scaly or separated by cracks into distinct, island-like areas (areolate). The islands (areoles) are 1⁄64″ to 1⁄32″ (0.5 to 1.0 mm) wide and more or less round. They may be touching or more or less scattered. The lobes may be radiating out from the center or randomly oriented; flat, concave, convex, or wavy; and merged with adjacent lobes or clearly separated. They are usually 1⁄16″ to 3⁄16″ (1.5 to 4.5 mm) long and 1⁄64″ (0.5 to 0.6 mm) wide, but they can be up to ¼″ (6.0 mm) long and 1⁄16″ (1.5 mm) wide. The upper surface is grayish yellow green to pale greenish yellow, or grayish yellow. It is more yellow towards the lobe tips. The lower surface may be mostly white, pale yellow, or pale brown. It is always at least partly bluish green to black. Spore-bearing reproductive structures (apothecia) can be few to crowded toward the center of the thallus. Each areole may have one to several apothecia. They are disk-like, stalkless, partially submersed in the thallus, and moderate sized, 1⁄32″ to ⅛″ (0.8 to 2.3 mm) in diameter. The color is variable, and different colors may appear on the same thallus. They may be light yellow to dark yellow, orangish brown, reddish brown, or blackish, and they are sometimes greenish gray near the margin. They are usually flat but sometimes convex, and they are either dull or shiny. They may be partially or almost completely covered with grayish powder (pruinose) or have no powder. |
Similar Species |
Ecology |
Substrate |
Rock |
Growth Form |
Crusticose |
Habitat |
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Hosts |
Basalt, pumice, rhyolite, granite, sandstone, and limestone |
Distribution |
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Sources |
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| 3/14/2025 | ||
Occurrence |
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Common and widespread |
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Taxonomy |
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Kingdom |
Fungi (fungi) |
Subkingdom |
Dikarya |
Phylum |
Ascomycota (sac fungi) |
Subphylum |
Pezizomycotina (sac fungi amd lichens) |
Class |
Lecanoromycetes (common lichens) |
Subclass |
Lecanoromycetidae (shield lichens, sunburst lichens, rosette lichens, and allies) |
Order |
Lecanorales (shield lichens, rim lichens, and allies) |
Family |
Lecanoraceae (rim lichens, disc lichens, and allies) |
Genus |
Protoparmeliopsis |
Mycobiont |
Protoparmeliopsis muralis |
Photobiont |
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Subordinate Taxa |
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Several varieties have been described in the past, but no varieties are currently recognized. |
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Synonyms |
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Acarospora squamulosa f. albomarginata Callopisma pusillum Caloplaca murorum f. pusilla Caloplaca tegularis var. pusilla Gasparrinia saxicola Lecanora alboeffigurata Lecanora albomarginata Lecanora diffracta Lecanora dubyi Lecanora galactina f. muralis Lecanora muralis Lecanora murorum var. pusilla Lecanora saxicola Lecanora semitensis Lecanora versicolor Lichen diffractus Lichen muralis Lichen peltatus ssp. diffracta Lichen saxicola Lichen versicolor Lobaria muralis Lobaria saxicola Lobaria versicolor Parmelia muralis Parmelia saxicola Parmularia albomarginata Parmularia muralis Patellaria muralis Placodium albomarginatum Placodium diffractum Placodium murale Placodium murorum var. pusillum Placodium ochroleucum var. muralis Placodium saxicola Placodium saxicolum var. lofotensis Placodium versicolor Placolecanora albomarginata Placolecanora albomarginata Placolecanora muralis Placolecanora versicolor Protoparmeliopsis muralis var. diffracta Protoparmeliopsis muralis var. dubyi Protoparmeliopsis muralis var. schneebergensis Protoparmeliopsis versicolor Psora muralis Psoroma murale Psoroma saxicola Squamaria albomarginata Squamaria carphinea var. dubyi Squamaria diffracta Squamaria muralis Squamaria riparia var. muralis Squamaria saxicola Squamaria versicolor Squamarina provincialis |
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Common Names |
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Stonewall Rim Lichen |
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Glossary
Apothecium
An open, disk-shaped or cup-shaped, reproductive structure, with spore sacs on the upper surface, that produces spores for the fungal partner of a lichen. Plural: apothecia.
Areolate
In mushrooms, the cap surface cracked creating block-like patches similar to dried mud. In lichens: the surface sharply divided into islands separated by cracks.
Foliose
Leaf-like; referring to lichens with thin, flat, leaf-like growths divided into lobes which are free from the substrate.
Pruinescence
A waxy or powdery dust or bloom that covers the underlying coloration and gives a dusty or frosty appearance. Adjective: pruinose.
Thallus
In lichens: The vegetative body of a lichen composed of both the alga and the fungus. In liverworts: a flat, relatively undifferentiated plant body. Plural: thalli.
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Dan W. Andree |
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Lichens on rock at... This was taken at the Northern Tallgrass Prairie NWR Pavia Unit today. It’s kind a greenish gray on a boulder out there. |
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Other Videos |
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Stonewall Rim lichen growing on the sidewalk |
About
Apr 28, 2024 Stonewall Rim Scientific Name: Protoparmeliopsis Muralis Type: Lichen Habitat: From sea level to approximately 10,000 feet in elevation, typically on rocky surfaces or bark Range: Native to North America, including northern California and the Washoe County area Status: Vulnerable to critically impaired This species is NATIVE to the Truckee Meadows. Identification: Stonewall rim is a type of common lichen. Lichens are complex organisms that arise from symbiotic relationships between fungi and a photosynthesizer, like algae. This crustose lichen will strongly adhere to a surface, like rock or bark, and form a crust-like (crustose) layer that is very difficult to separate from the surface without destroying the lichen itself. Stonewall rim tends to grow in “rosettes,” which is a circular arrangement of leaves that share a center point, and can grow all over the world. This lichen generally appears pale whitish to greenish yellow, has a shiny or waxy surface, and looks to be made up of tiny disc-like fruiting bodies called “apothecia.” Most of the colored bodies will be towards the center with the paler whites towards the edges. Fast Facts: “Lecanora Muralis” is no longer the active taxon for this lichen but can be used for previously existing research. The current scientific name is Protoparmeliopsis Muralis. |
Rozetnik murowy (Protoparmeliopsis muralis / Lecanora muralis) - 28.01.2022, Nowa Huta, Kraków. |
About
Jan 28, 2022 Rozetnik murowy / Misecznica murowa (Protoparmeliopsis muralis / Lecanora muralis) - 28.01.2022, Nowa Huta, Kraków. |
Visitor Sightings |
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Dan W. Andree |
Location: Frenchman’s Bluff SNA |
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Dan W. Andree |
Location: Northern Tallgrass Prairie NWR, Pavia Unit This was taken at the Northern Tallgrass Prairie NWR Pavia Unit today. It’s kind a greenish gray on a boulder out there. |
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Created: 3/14/2025 Last Updated: © MinnesotaSeasons.com. All rights reserved. |