North America Native Plant

Disc Lichen

Botanical name: Buellia curatellae

USDA symbol: BUCU3

Habit: lichen

Native status: Native to North America  

Synonyms: Buellia conspirans (Nyl.) Vain. (BUCO7)   

Disc Lichen: The Tiny Garden Guardian You Never Knew You Had Have you ever noticed small, disc-like spots dotting the bark of your trees or garden rocks? Meet the disc lichen (Buellia curatellae), a fascinating little organism that’s probably already living in your landscape without you even realizing it! What ...

Disc Lichen: The Tiny Garden Guardian You Never Knew You Had

Have you ever noticed small, disc-like spots dotting the bark of your trees or garden rocks? Meet the disc lichen (Buellia curatellae), a fascinating little organism that’s probably already living in your landscape without you even realizing it!

What Exactly Is Disc Lichen?

Here’s where things get interesting: disc lichen isn’t actually a plant at all! It’s a unique partnership between a fungus and algae, working together in perfect harmony. The fungus provides structure and protection, while the algae produces food through photosynthesis. Think of it as nature’s ultimate roommate situation.

Scientifically known as Buellia curatellae (and sometimes called by its synonym Buellia conspirans), this native North American species forms small, circular patches that look like tiny gray-brown discs scattered across surfaces.

Where You’ll Find This Native Treasure

Disc lichen is native to North America and tends to favor the eastern regions of the continent. You’ll typically spot it making itself at home on:

  • Tree bark (especially older, established trees)
  • Rocky surfaces
  • Stone walls or garden features
  • Wooden structures that have weathered naturally

How to Identify Disc Lichen in Your Garden

Spotting disc lichen is like finding nature’s tiny artwork. Look for these telltale signs:

  • Small, round, disc-shaped structures typically 1-3mm across
  • Gray-brown to dark brown coloration
  • Flat or slightly raised appearance
  • Often found in clusters or scattered patterns
  • Grows directly on the surface without roots or stems

Is Disc Lichen Good for Your Garden?

Absolutely! While you might not have invited disc lichen to your garden party, it’s actually a wonderful guest to have around. Here’s why:

Air Quality Indicator: Lichens are incredibly sensitive to air pollution. Finding disc lichen in your garden is like getting a gold star for clean air quality. They simply won’t survive in polluted environments, so their presence means you’re breathing the good stuff.

Ecosystem Benefits: While disc lichen doesn’t attract pollinators like flowering plants, it plays its own important ecological role by contributing to the biodiversity of your garden’s microhabitat.

Natural Beauty: These tiny organisms add subtle texture and natural patina to surfaces, creating that authentic, weathered look that many gardeners spend years trying to achieve artificially.

The Hands-Off Approach to Disc Lichen

Here’s the thing about disc lichen: you can’t really grow it, and you don’t need to! Unlike traditional garden plants, lichens establish themselves naturally when conditions are right. There’s no planting, watering, or fertilizing involved.

If you want to encourage lichen growth in your garden:

  • Maintain good air quality (avoid excessive use of chemicals)
  • Provide suitable surfaces like natural stone or weathered wood
  • Be patient – lichens grow very slowly
  • Resist the urge to clean them off surfaces

Living Harmoniously with Your Lichen Neighbors

The best approach to disc lichen is simply to appreciate it. These remarkable organisms are doing their own thing, contributing to your garden’s ecosystem without asking for anything in return. They’re like the perfect low-maintenance garden residents!

Next time you’re strolling through your garden, take a moment to look closely at your trees and rocks. Those tiny disc-shaped spots aren’t just random marks – they’re living partnerships that have been quietly enhancing your outdoor space all along.

Disc Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Physciaceae Zahlbr.

Genus

Buellia De Not. - disc lichen

Species

Buellia curatellae Malme - disc lichen

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