SafePlants

Cracked Lichen (Acarospora spp.)

The term "cracked lichen" is a common name applied to various lichen species, especially those belonging to the genus Acarospora. These lichens are known for their distinctive appearance, often resembling a cobblestone road or cracked paint.

Considerations for Pets and Children

• The text mentions lichens growing on rocks, trees, and other surfaces. Depending on the environment, these surfaces could have sharp edges or be otherwise hazardous.
• Some lichens, including cracked lichens, can form a crust that cracks during growth. These cracks could potentially contain small, loose pieces.

Taxonomy and Nomenclature

• Scientific Name: Primarily Acarospora spp., but also other species with "cracked" texture.
• Common Names: Cobblestone lichens, cracked lichens.
• Family: Acarosporaceae, Parmeliaceae
• Examples:
  • Acarospora hilaris
  • Acarospora schleicheri (Schleicher's Cracked Lichen)
  • Acarospora aeruginosa
  • Acarospora arenosa
  • Acarospora gallica (Gallic Cracked Lichen)
  • Acarospora impressula
  • Acarospora nodulosa (Nodule Cracked Lichen)
  • Acarospora socialis
  • Acarospora badiofusca

Distribution and Habitat

• Cracked lichens are found in various locations, including:
  • The Rocky Mountains (for narcotic lichen)
  • Britain and Ireland
  • Planalto das Cezaredas, Portugal
  • Olympic Peninsula
• They commonly grow on rocks, including granite, dolomite, and sandstone cliffs, as well as tree bark.
• Narcotic lichen is specifically found in desolate parts of the Rockies.

Morphological Characteristics

• The lichen thallus (body) is often made up of separate lumps that grow together, creating a continuous, cracked surface.
• The thallus can be crust-like and areolate, meaning it's divided into small, distinct areas.
• Some species have a white thallus that appears cracked or frosted.
• Some cracked lichens have bright yellow areoles with small, dark apothecia (fruiting bodies) immersed within.

Interactions with Other Organisms

• Lichens can contribute to the breakdown of rocks through slow erosion.
• They are found in association with moss and fungi.
• The text mentions scentless mayweed growing on cracked lichen-covered sandstone.

Further Information

• plants.usda.gov
• HortHub.com
• Mushroom Observer (mushroomobserver.org)
• Catalogue of Life: 2012 Annual Checklist