SafePlants

Dust Lichens: A Closer Look

Dust lichens encompass lichens belonging to either the genus Chrysothrix or Lepraria. These lichens are characterized by their dust-like appearance, forming a thin layer on the substrate.

Considerations for Pets

• Dust lichens often grow on tree bark and rocks, which pets may encounter during outdoor explorations.
• Some varieties, such as the "fluffy" dust lichens, have a powdery or fuzzy texture, which might be interesting to pets.

Considerations for Children

• The powdery texture of dust lichens might be appealing for children to touch.

Nomenclature and Taxonomy

• Genus: Chrysothrix, Lepraria
• Family: Stereocaulaceae (for some Lepraria species)
• Order: Lecanorales (for some Lepraria species)
• Class: Lecanoromycetes (for some Lepraria species)
• Phylum: Ascomycota (for some Lepraria species)
• Kingdom: Fungi
• Synonyms: Lepraria chlorina (synonym for Chrysothrix chlorina)

Common Species and Names

• Lepraria incana: Dust Lichen
• Lepraria lobificans: Fluffy Dust Lichen
• Chrysothrix candelaris: Mustard Powder Lichen, Gold Dust Lichen
• Chrysothrix chlorina: Sulphur Dust Lichen

Morphological Characteristics

• Crustose lichens, forming a crust-like layer on the substrate.
• Appearance ranges from yellowish-green to pale green, blue-grey, or greenish.
• Covered with soredia (small clusters of algal cells and fungal filaments for asexual reproduction).
• Some species appear "fluffy" due to the presence of soredia.
• Sterile lichens that do not produce ascocarps (fruiting bodies).

Reproduction

• Reproduce asexually through soredia and isidia (another type of asexual propagule).

Distribution and Habitat

• Found in various locations, including:
  • Eagle Lake in Morehead, Kentucky
  • Washington Co., Maryland
  • Charles Co., Maryland
  • Pacific Northwest (on evergreen trees, notably Douglas Fir)
• Commonly grows on:
  • Tree bark (especially Chrysothrix candelaris)
  • Shaded rocks
  • Mosses
  • Tree trunks
  • Old barns
• Prefers moist environments.
• Can be found in deciduous forests.

Ecological Role

• Some species (e.g., Lepraria finkii, Lepraria lobificans) are tolerant of moderate to high levels of pollution and can be used as pollution indicators.

Quirky Facts

• Some dust lichens can be used as dyes.
• Dust lichens are sterile crustose lichens that consist only of a layer of sordia, thus appearing as a layer of think dust on the substrate.

Further Information

• Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014
• Catalogue of Life: 2012 Annual Checklist