North America Native Plant

Catillaria Lichen

Botanical name: Catillaria chalybeia

USDA symbol: CACH28

Habit: lichen

Native status: Native to North America  

Discovering Catillaria Lichen: A Tiny Garden Inhabitant You Never Knew You Had Have you ever taken a close look at the rocks, stone walls, or concrete surfaces around your garden and noticed what looks like thin, crusty patches of grayish material? You might be looking at catillaria lichen, a fascinating ...

Discovering Catillaria Lichen: A Tiny Garden Inhabitant You Never Knew You Had

Have you ever taken a close look at the rocks, stone walls, or concrete surfaces around your garden and noticed what looks like thin, crusty patches of grayish material? You might be looking at catillaria lichen, a fascinating organism that’s probably been quietly living in your outdoor spaces all along!

What Exactly Is Catillaria Lichen?

Catillaria chalybeia, commonly known as catillaria lichen, is one of those amazing organisms that challenges our typical understanding of what constitutes a plant. Technically, it’s not a plant at all – it’s a lichen! Lichens are actually a partnership between fungi and algae (or sometimes cyanobacteria), working together in what scientists call a symbiotic relationship. Think of it as nature’s ultimate roommate situation that actually works out perfectly.

This particular lichen is native to North America and has been quietly colonizing rocky surfaces across the continent for countless years. Unlike the plants you might deliberately choose for your garden, catillaria lichen chooses you – or rather, it chooses your stone surfaces.

Geographic Distribution

Catillaria lichen can be found throughout various regions of North America, thriving in temperate climates where conditions are just right for this unique organism to establish itself on suitable surfaces.

What Does It Look Like?

Identifying catillaria lichen is like becoming a detective in your own backyard. Here’s what to look for:

  • Thin, crusty patches that appear almost painted onto rock surfaces
  • Grayish to dark coloration, sometimes with a slightly metallic sheen
  • Smooth to slightly rough texture that feels different from moss or algae
  • Typically found on exposed rock faces, stone walls, or concrete surfaces
  • Forms irregular patches rather than distinct shapes

Is Catillaria Lichen Beneficial in Your Garden?

While you can’t exactly plant catillaria lichen in your flower beds, its presence is actually a good sign! Lichens are excellent indicators of air quality – they’re quite sensitive to pollution, so finding them thriving in your garden suggests you have relatively clean air.

Here are some ways this tiny organism benefits your outdoor space:

  • Acts as a natural air quality monitor
  • Contributes to biodiversity in your garden ecosystem
  • Helps with slow weathering and soil formation processes
  • Provides habitat for tiny invertebrates
  • Adds subtle natural character to stone surfaces

Can You Grow Catillaria Lichen?

Here’s where things get interesting – you can’t actually cultivate or plant catillaria lichen like you would a tomato or a rose bush. This lichen establishes itself naturally when conditions are right, and trying to transplant or encourage it typically doesn’t work.

However, if you want to create conditions where lichens like this might naturally appear, you can:

  • Maintain clean air quality around your property
  • Avoid using harsh chemicals on stone surfaces
  • Allow natural stone surfaces to weather without frequent cleaning
  • Be patient – lichen establishment is a very slow process

Living Alongside Your Lichen Neighbors

The best approach to catillaria lichen is simply to appreciate it as part of your garden’s natural ecosystem. It’s not harmful to surfaces (despite what some people think), and it’s certainly not something you need to remove or control.

Think of finding catillaria lichen in your garden as discovering a tiny, ancient community that’s been quietly doing its thing long before you planted your first flower. It’s a reminder that our gardens are complex ecosystems filled with life forms both big and small, obvious and subtle.

Next time you’re walking around your garden, take a moment to look closely at your stone surfaces. You might just spot these remarkable organisms and gain a new appreciation for the incredible diversity of life that calls your outdoor space home!

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 chalybeia (Borrer) A. Massal. - 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