SafePlants

Cobblestone Lichen/Cracked Lichen (Acarospora)

The term "cobblestone lichen" or "cracked lichen" refers to various species within the genus Acarospora. These lichens are named for their distinctive appearance, often resembling a cobblestone road or cracked paint.

Considerations for Pets

• Lichens are often found on rocks and trees in outdoor environments where pets may explore.
• Some descriptions mention lichens growing on bark, which can be flaky.

Considerations for Children

• Lichens can grow on rocks, potentially making surfaces uneven or slippery.

Taxonomy and Nomenclature

• Genus: Acarospora
• Family: Acarosporaceae
• Common Names: Cobblestone Lichen, Cracked Lichen
• Examples of species:
  • Acarospora hilaris
  • Acarospora aeruginosa
  • Acarospora albomarginata
  • Acarospora arenosa
  • Acarospora schleicheri (Schleicher's Cracked Lichen)
  • Acarospora gallica (Gallic Cracked Lichen)
  • Acarospora impressula
  • Acarospora nodulosa
  • Acarospora socialis
  • Acarospora badiofusca

Distribution and Habitat

• These lichens are found in various locations, including inhospitable regions.
• They grow on rocks.
• They can be found on sandstone cliffs.
• They have been documented in:
  • Britain
  • Ireland
  • Idaho
  • Rocky Mountains
  • Planalto das Cezaredas, Portugal

Morphological Characteristics

• Acarospora species exhibit a cracked-areolate thallus, where a continuous crust cracks during growth.
• The lichen thallus may initially consist of separate lumps that grow together to form a continuous, cracked surface.
• Some species have angular, bright yellow aeroles and small, darker apothecia immersed in the aeroles.
• Some species have white lines on the surface giving it a cracked appearance.
• Buellia subalbula is mentioned as having a distinctive white, cracked thallus that often appears slightly frosted.

Ecological Role

• Lichens contribute to the breakdown of rocks, albeit slowly. The lichen work very slowly to break down rocks.

Quirky Facts

• It can take decades for them to grow over a single rock.

Further Information

• Mushroom Observer: http://mushroomobserver.org/