North America Native Plant

Catillaria Lichen

Botanical name: Catillaria lenticularis

USDA symbol: CALE42

Habit: lichen

Native status: Native to North America  

Catillaria Lichen: The Tiny Garden Guest You Can’t Plant (But Should Welcome) Have you ever noticed small, crusty patches on the bark of your trees and wondered what they were? Meet the catillaria lichen (Catillaria lenticularis) – a fascinating organism that might already be calling your garden home without you ...

Catillaria Lichen: The Tiny Garden Guest You Can’t Plant (But Should Welcome)

Have you ever noticed small, crusty patches on the bark of your trees and wondered what they were? Meet the catillaria lichen (Catillaria lenticularis) – a fascinating organism that might already be calling your garden home without you even realizing it!

What Exactly Is Catillaria Lichen?

Here’s where things get interesting: catillaria lichen isn’t actually a plant at all! It’s a lichen – a remarkable partnership between a fungus and algae working together as one organism. Think of it as nature’s ultimate roommate situation, where both parties benefit from the arrangement.

This native North American species forms thin, crusty patches on tree bark that can range from pale grayish-white to subtle yellowish tones. While it might not win any beauty contests, this unassuming little organism is actually quite special.

Where You’ll Find It

Catillaria lenticularis is native to North America and can be found across temperate regions of the continent. It has a particular fondness for the bark of various tree species, where it settles in for the long haul.

How to Spot Catillaria Lichen

Identifying catillaria lichen is all about knowing what to look for:

  • Small, thin, crusty patches on tree bark
  • Pale grayish-white to yellowish coloration
  • Smooth to slightly rough texture
  • Closely adhered to the bark surface
  • Often forms irregular, spreading patches

Is It Good for Your Garden?

Absolutely! While you can’t plant or cultivate catillaria lichen (trust us, we wish you could), having it appear naturally in your garden is actually fantastic news. Here’s why:

Lichens like Catillaria lenticularis are incredibly sensitive to air pollution. Their presence is basically nature’s way of giving your garden a gold star for air quality. If you spot these little patches on your trees, it means your local environment is clean enough to support these pollution-sensitive organisms.

The Reality Check: You Can’t Grow It

Here’s the thing about lichens – they’re not something you can pick up at the garden center or order online. Catillaria lenticularis will only appear in your garden if conditions are just right, and there’s absolutely nothing you can do to hurry the process along.

These lichens:

  • Cannot be planted or transplanted
  • Don’t respond to fertilizers or care
  • Appear naturally when air quality and environmental conditions are suitable
  • Take their sweet time establishing themselves

Creating Lichen-Friendly Conditions

While you can’t plant catillaria lichen directly, you can create conditions that might encourage it to show up:

  • Maintain mature trees with textured bark
  • Avoid using harsh chemicals or pesticides in your garden
  • Keep air quality as clean as possible
  • Be patient – lichens operate on their own timeline

Don’t Panic If You Find It

Some gardeners worry that lichens on their trees indicate disease or damage. Rest assured – catillaria lichen is completely harmless to your trees! It’s simply using the bark as a place to live, not as a food source. Think of it as a very polite tenant that pays rent by indicating your garden has excellent air quality.

The Bottom Line

Catillaria lichen is one of those wonderful garden surprises that you can’t plan for but should definitely celebrate when it arrives. It’s a sign that your outdoor space is healthy, your air is clean, and your garden is mature enough to support these fascinating organisms. So next time you spot those small, crusty patches on your trees, give them a little nod of appreciation – they’re proof that your garden is doing something right!

Catillaria Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Catillariaceae Hafellner

Genus

Catillaria A. Massal. - catillaria lichen

Species

Catillaria lenticularis (Ach.) Th. Fr. - catillaria lichen

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