North America Native Plant

Myriotrema Lichen

Botanical name: Myriotrema compunctum

USDA symbol: MYCO7

Habit: lichen

Native status: Native to North America  

Myriotrema Lichen: A Fascinating Indicator of Forest Health Have you ever noticed crusty, whitish patches dotting the bark of old trees during your woodland walks? You might have been looking at Myriotrema compunctum, commonly known as myriotrema lichen. This remarkable organism isn’t actually a plant at all—it’s a lichen, a ...

Myriotrema Lichen: A Fascinating Indicator of Forest Health

Have you ever noticed crusty, whitish patches dotting the bark of old trees during your woodland walks? You might have been looking at Myriotrema compunctum, commonly known as myriotrema lichen. This remarkable organism isn’t actually a plant at all—it’s a lichen, a fascinating partnership between fungi and algae that tells us a lot about the health of our forests.

What Exactly Is Myriotrema Lichen?

Myriotrema lichen is a crustose lichen, meaning it forms a tight, crusty layer that’s firmly attached to its host surface. Unlike the leafy or shrubby lichens you might be more familiar with, this species creates flat, patch-like growths that can almost look like someone splashed pale paint on tree bark. The fungal partner provides structure and protection, while the algal partner photosynthesizes to create food for both—it’s nature’s perfect roommate situation!

This lichen is native to North America and plays an important role in forest ecosystems. What makes it particularly special is its sensitivity to air pollution, making it a natural indicator of environmental health.

Spotting Myriotrema Lichen in the Wild

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

  • Look for whitish to pale gray, crusty patches on tree bark
  • The surface appears somewhat rough or granular
  • Small, dark, dot-like structures (called perithecia) are scattered across the surface—these are the lichen’s fruiting bodies
  • It typically grows on the bark of mature deciduous trees
  • You’re most likely to find it in older, undisturbed forest areas

Is Myriotrema Lichen Beneficial for Your Garden?

While you can’t cultivate myriotrema lichen in your garden like you would a flower or shrub, its presence is actually a wonderful sign! Here’s why this lichen is beneficial:

  • Air quality indicator: Its presence suggests you have clean air in your area
  • Ecosystem health: Indicates a mature, stable forest ecosystem
  • Biodiversity support: Contributes to the complex web of forest life
  • Minimal impact: Doesn’t harm its host trees—it’s simply along for the ride

Why You Might Find It Near Your Property

If you’re lucky enough to spot myriotrema lichen on trees around your property, congratulations! This means you’re living in an area with good air quality and mature trees. The lichen requires:

  • Clean air with minimal pollution
  • Adequate humidity and moisture
  • Mature trees with stable bark surfaces
  • Relatively undisturbed forest conditions

Supporting Lichen-Friendly Environments

While you can’t plant myriotrema lichen, you can certainly create conditions that support lichens in general:

  • Preserve mature trees on your property
  • Avoid using pesticides and chemicals that could affect air quality
  • Maintain natural forest understory when possible
  • Support conservation efforts for old-growth forests

A Living Testament to Clean Air

Think of myriotrema lichen as nature’s air quality monitor. Its presence tells a story of clean air, healthy forests, and balanced ecosystems. While you won’t be adding it to your shopping list for garden plants, appreciating and protecting the conditions that allow it to thrive makes you a steward of forest health.

Next time you’re walking through mature woodlands, take a moment to appreciate these crusty, unassuming patches on tree bark. They’re quietly doing their part to maintain the intricate balance of forest life, one partnership between fungi and algae at a time.

Myriotrema Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Graphidales

Family

Thelotremataceae Stizenb.

Genus

Myriotrema Fée - myriotrema lichen

Species

Myriotrema compunctum (Ach.) Hale - myriotrema lichen

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