North America Native Plant

Desert Aspicilia

Botanical name: Aspicilia desertorum

USDA symbol: ASDE19

Habit: lichen

Native status: Native to North America  

Synonyms: Lecanora desertorum Krempelh. (LEDE15)   

Desert Aspicilia: The Rock-Loving Lichen You Might Already Have in Your Garden Have you ever noticed those crusty, whitish-gray patches on rocks in your garden or local hiking trails? Meet desert aspicilia (Aspicilia desertorum), a fascinating lichen that’s been quietly doing its thing on stone surfaces across western North America. ...

Desert Aspicilia: The Rock-Loving Lichen You Might Already Have in Your Garden

Have you ever noticed those crusty, whitish-gray patches on rocks in your garden or local hiking trails? Meet desert aspicilia (Aspicilia desertorum), a fascinating lichen that’s been quietly doing its thing on stone surfaces across western North America. While you can’t exactly plant this interesting organism in your flower beds, understanding what it is and recognizing its presence can give you valuable insights into your local ecosystem.

What Exactly Is Desert Aspicilia?

Desert aspicilia isn’t a plant in the traditional sense – it’s actually a lichen! Lichens are remarkable partnerships between fungi and algae (or sometimes cyanobacteria) that work together to create something entirely new. The fungal partner provides structure and protection, while the algae partner produces food through photosynthesis. It’s like nature’s ultimate roommate situation, and it’s been working beautifully for millions of years.

This particular lichen goes by the scientific name Aspicilia desertorum, though it was previously known as Lecanora desertorum. As its common name suggests, it’s perfectly adapted to desert and semi-arid conditions.

Where You’ll Find Desert Aspicilia

Desert aspicilia is native to North America and has been documented growing in Idaho, though it likely occurs in other western states with similar arid conditions. This lichen is a true rock dweller, making its home on various stone surfaces in dry environments.

How to Identify Desert Aspicilia

Spotting desert aspicilia is fairly straightforward once you know what to look for:

  • Forms crusty, patch-like growths directly on rock surfaces
  • Typically whitish-gray to pale gray in color
  • Has a somewhat granular or warty texture
  • Grows tightly attached to its rock substrate
  • Often found in areas with good air circulation and minimal moisture

The patches can vary in size from small spots to larger colonies that may cover significant portions of rock faces.

Is Desert Aspicilia Beneficial to Your Garden?

While you won’t be adding desert aspicilia to your shopping list at the local nursery, its presence in your landscape can actually be quite beneficial:

  • Air quality indicator: Lichens are sensitive to air pollution, so their presence suggests relatively clean air in your area
  • Ecosystem pioneer: They help break down rock surfaces over time, contributing to soil formation
  • Natural beauty: These organisms add subtle texture and visual interest to rock features
  • Low maintenance: They require absolutely no care from you – they’re completely self-sufficient

Living with Desert Aspicilia

The beauty of desert aspicilia is that it asks nothing of you as a gardener. You can’t plant it, you can’t water it, and you certainly can’t fertilize it. If you have suitable rock surfaces and the right climate conditions, it may simply appear on its own over time.

If you do notice these lichens on rocks in your landscape, consider it a good sign! Their presence indicates that your local environment is healthy enough to support these sensitive organisms. Simply appreciate them for the quiet, steady work they’re doing in breaking down rock and contributing to the natural processes in your garden ecosystem.

The Bottom Line

Desert aspicilia might not be the showiest addition to your landscape, but it represents something pretty special – a successful partnership that has been thriving in harsh conditions for countless years. Next time you’re examining the rocks in your garden or on your favorite hiking trail, take a moment to appreciate these unassuming but remarkable organisms. They’re a reminder that nature finds a way to make life work in even the most challenging environments.

Desert Aspicilia

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Hymeneliaceae Körb.

Genus

Aspicilia A. Massal. - rimmed lichen

Species

Aspicilia desertorum (Krempelh.) Mereschk. - desert aspicilia

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA