SafePlants

Cracked Lichens: A Diverse Group of Organisms

The term "cracked lichen" refers to various lichen species, often characterized by their appearance resembling cracked cobblestones or old paint.

Considerations for Pets

• Lichens often grow on rocks, bark, and soil, environments accessible to pets.
• The thallus (lichen body) can crack during growth, potentially creating small, detached pieces.

Considerations for Children

• Lichens commonly grow on rocks and trees, which children may explore.
• The cracked surface of the lichen could potentially detach in small pieces.

Common Names

• Cracked Lichen
• Cobblestone Lichen

Scientific Names and Taxonomy

• Genus: Acarospora
• Family: Acarosporaceae
• Examples of Acarospora species referred to as "cracked lichens":
  • 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
• Kingdom: Fungi
• Phylum: Ascomycota
• Class: Lecanoromycetes
• Order: Agyriales

Distribution and Habitat

• Acarospora schleicheri (Schleicher's Cracked Lichen) is found in the Rocky Mountains.
• Some varieties grow on granite.
• Others can be found on sandstone cliffs.

Morphological Characteristics

• Cracked lichens develop a "cracked-areolate" thallus as they grow.
• The lichen thallus initially consists of separate lumps that often merge to form a continuous, cracked surface.
• Buellia subalbula is noted for its white, cracked thallus, often appearing slightly frosted.
• Some species have angular, bright yellow areoles with small, darker apothecia immersed within them.

Interactions with Other Organisms

• Lichens can contribute to the breakdown of rocks over time.
• They can grow on various surfaces, including bark and wooden planks, sometimes alongside mosses and fungi.
• Tripleurospermum inodorum (scentless mayweed) can grow on cracked lichen-covered sandstone cliffs.

Quirky Facts

• One source humorously references the potential (though unlikely) of a "sheep-based drug cartel" in relation to "narcotic lichen".

Resources and Further Information

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