North America Native Plant

Myriotrema Lichen

Botanical name: Myriotrema laeviusculum

USDA symbol: MYLA7

Habit: lichen

Native status: Native to North America  

Synonyms: Leptotrema laeviusculum (Nyl.) Zahlbr. (LELA28)   

Myriotrema Lichen: A Fascinating Tree-Dwelling Organism in Your Backyard Have you ever noticed those peculiar, crusty patches on tree bark during your garden strolls? You might be looking at Myriotrema laeviusculum, commonly known as myriotrema lichen. While you won’t find this fascinating organism at your local nursery, understanding what it ...

Myriotrema Lichen: A Fascinating Tree-Dwelling Organism in Your Backyard

Have you ever noticed those peculiar, crusty patches on tree bark during your garden strolls? You might be looking at Myriotrema laeviusculum, commonly known as myriotrema lichen. While you won’t find this fascinating organism at your local nursery, understanding what it is and recognizing its presence can add a whole new dimension to appreciating the natural world right in your own landscape.

What Exactly Is Myriotrema Lichen?

Let’s clear up a common misconception right away – lichens aren’t plants! Myriotrema laeviusculum is actually a remarkable partnership between a fungus and an algae (or sometimes cyanobacteria), living together in perfect harmony. This symbiotic relationship creates what we see as a lichen, and it’s been perfecting this cooperation for millions of years.

This particular lichen species is native to North America, making it a natural part of our ecosystem. You might also see it referred to by its scientific synonym, Leptotrema laeviusculum, in older field guides or research papers.

Where You’ll Find This Lichen

Myriotrema lichen has made its home across eastern North America, thriving in temperate forest environments. It’s particularly fond of settling on the bark of various tree species, where it forms thin, pale grayish-white crusts that might initially go unnoticed by casual observers.

How to Identify Myriotrema Lichen

Spotting this lichen takes a bit of detective work, but once you know what to look for, you’ll start seeing it everywhere! Here are the key identifying features:

  • Forms thin, crusty patches on tree bark
  • Pale grayish-white coloration
  • Small, round to oval fruiting bodies (called perithecia) scattered across the surface
  • Smooth, relatively flat appearance against the bark
  • Typically found on the bark of living trees rather than dead wood

Is Myriotrema Lichen Beneficial to Your Garden?

Absolutely! While you can’t plant or cultivate myriotrema lichen (and trust me, you wouldn’t want to try), its presence in your landscape is actually a wonderful sign. Lichens are incredibly sensitive to air pollution, so finding them growing happily on your trees indicates that your local air quality is pretty good.

Here’s why you should welcome these tiny tenants:

  • They’re excellent indicators of environmental health
  • They don’t harm their host trees – they’re just hitching a ride
  • They add biodiversity to your landscape ecosystem
  • They provide food and nesting materials for various small wildlife species
  • They contribute to the natural, wild appearance that many gardeners strive for

Living Alongside Myriotrema Lichen

The beauty of myriotrema lichen is that it requires absolutely zero maintenance from you. In fact, the best thing you can do is simply leave it alone! This lichen knows exactly what it’s doing and has been thriving without human intervention for far longer than we’ve been gardening.

If you’re lucky enough to spot this lichen in your landscape, consider it a badge of honor – you’re providing habitat for one of nature’s most successful partnerships. Just remember to observe and appreciate rather than disturb, as lichens grow incredibly slowly and can take years to recover from damage.

So next time you’re out admiring your trees, take a closer look at their bark. You might just discover you’re hosting some remarkable microscopic roommates that have been quietly contributing to your garden’s ecosystem all along!

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 laeviusculum (Nyl.) 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