North America Native Plant

Disk Lichen

Botanical name: Trapelia mooreana

USDA symbol: TRMO14

Habit: lichen

Native status: Native to North America  

Synonyms: Lecidea brujeriana (D. Dietr.) Leight. (LEBR10)  ⚘  Lecidea lopadioides (Th. Fr.) Grumm. (LELO7)  ⚘  Trapelia brujeriana (D. Dietr.) M. Choisy (TRBR10)  ⚘  Trapelia torellii (Anzi) Hertel (TRTO2)   

Disk Lichen: The Tiny Garden Guest You Never Invited (But Should Welcome) Have you ever noticed small, crusty patches on rocks in your garden and wondered what they were? Meet the disk lichen, scientifically known as Trapelia mooreana – a fascinating organism that’s probably been quietly living in your outdoor ...

Disk Lichen: The Tiny Garden Guest You Never Invited (But Should Welcome)

Have you ever noticed small, crusty patches on rocks in your garden and wondered what they were? Meet the disk lichen, scientifically known as Trapelia mooreana – a fascinating organism that’s probably been quietly living in your outdoor space without you even realizing it!

What Exactly Is Disk Lichen?

Here’s where things get interesting: disk lichen isn’t actually a plant at all! It’s a lichen – a unique partnership between a fungus and an algae that work together like the ultimate power couple. The fungus provides structure and protection, while the algae handles the food production through photosynthesis. It’s nature’s version of a perfect roommate situation.

This particular species goes by several scientific names throughout history, including Lecidea brujeriana and Trapelia brujeriana, which shows just how much scientists have debated its classification over the years.

Where You’ll Find This Little Survivor

Disk lichen is native to North America, making it a true local resident in many gardens and natural areas across the continent. You’ll typically spot it doing its thing on rock surfaces, stone walls, and sometimes even concrete structures where it forms small, crusty patches.

Spotting Disk Lichen in Your Garden

Identifying disk lichen is easier than you might think once you know what to look for:

  • Forms small, flat, crusty patches on rock surfaces
  • Grayish to brownish coloration
  • Features tiny, disk-like structures (called apothecia) that contain spores
  • Grows directly attached to its rock substrate
  • Usually measures just a few centimeters across

Is Disk Lichen Good for Your Garden?

The short answer? Absolutely! While you can’t exactly plant disk lichen (trust me, it doesn’t work that way), having it naturally occur in your garden is actually a wonderful sign. Here’s why you should celebrate these tiny tenants:

  • Air quality indicator: Lichens are incredibly sensitive to air pollution, so their presence suggests you have relatively clean air
  • Ecosystem support: They provide habitat for tiny insects and other microscopic creatures
  • Natural beauty: They add subtle texture and interest to stone surfaces
  • Soil formation: Over very long periods, they help break down rock surfaces, contributing to soil creation

Can You Grow Disk Lichen?

Here’s the thing about lichens – they’re not your typical garden plant. You can’t pop down to the nursery, pick up a pot of disk lichen, and plant it in your flower bed. These remarkable organisms establish themselves naturally when conditions are just right, and trying to cultivate them is nearly impossible.

Instead of trying to grow them, the best approach is to:

  • Leave existing lichen patches undisturbed
  • Avoid using harsh chemicals near stone surfaces where they grow
  • Maintain good air quality around your property
  • Be patient – lichens grow extremely slowly, sometimes just millimeters per year

Living Alongside Your Lichen Neighbors

If you’re lucky enough to have disk lichen naturally occurring in your garden, consider yourself fortunate! These slow-growing organisms have likely been there much longer than your garden, quietly doing their thing season after season.

The best way to support them is simply to let them be. Avoid scrubbing them off rocks or applying chemicals to areas where they’re growing. Think of them as nature’s living art – a subtle reminder that some of the most interesting garden residents are the ones that choose you, rather than the ones you choose.

So next time you’re wandering through your garden, take a moment to appreciate these tiny marvels. They may not be showy like your prize roses, but they’re doing important work and adding their own quiet charm to your outdoor space.

Disk Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Trapeliaceae M. Choisy ex Hertel

Genus

Trapelia M. Choisy - disk lichen

Species

Trapelia mooreana (Carroll) P. James - disk lichen

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