North America Native Plant

Mycoglaena Canadensis

Botanical name: Mycoglaena canadensis

USDA symbol: MYCA12

Habit: lichen

Native status: Native to North America  

Mycoglaena canadensis: The Tiny Lichen That’s Actually Great News for Your Garden Have you ever noticed small, crusty patches growing on the bark of trees in your yard and wondered what they were? If you live in eastern North America, there’s a good chance you’ve encountered Mycoglaena canadensis, a fascinating ...

Mycoglaena canadensis: The Tiny Lichen That’s Actually Great News for Your Garden

Have you ever noticed small, crusty patches growing on the bark of trees in your yard and wondered what they were? If you live in eastern North America, there’s a good chance you’ve encountered Mycoglaena canadensis, a fascinating little lichen that’s actually a wonderful indicator of your garden’s health!

What Exactly Is Mycoglaena canadensis?

First things first – Mycoglaena canadensis isn’t a plant in the traditional sense. It’s actually a lichen, which is a remarkable partnership between a fungus and an alga (or sometimes a cyanobacterium). Think of it as nature’s ultimate roommate situation, where both partners benefit from living together. The fungus provides structure and protection, while the alga produces food through photosynthesis.

This particular lichen is native to North America and forms small, crusty patches that typically appear grayish or whitish on tree bark and occasionally on rocks. While it doesn’t have a widely recognized common name, it’s part of a diverse group of crustose lichens that are found throughout our continent’s forests.

Where You’ll Find This Little Wonder

Mycoglaena canadensis makes its home primarily in the eastern regions of North America, particularly thriving in boreal and temperate forest environments. You’re most likely to spot it in areas with clean air and moderate humidity levels.

Is It Beneficial to Have in Your Garden?

Here’s the exciting part – finding Mycoglaena canadensis in your garden is actually fantastic news! This lichen serves as a natural air quality indicator. Lichens are incredibly sensitive to air pollution, particularly sulfur dioxide and other airborne toxins. When you see healthy lichens like Mycoglaena canadensis thriving on your trees, it’s a clear sign that your air quality is good.

Beyond being an environmental indicator, this lichen also:

  • Contributes to the overall biodiversity of your garden ecosystem
  • Provides microhabitat for tiny insects and other small creatures
  • Adds subtle texture and natural beauty to tree bark
  • Helps with minor soil formation as it slowly breaks down over time

How to Identify Mycoglaena canadensis

Spotting this lichen requires looking closely at tree bark, particularly on deciduous trees. Here’s what to look for:

  • Small, crusty patches that appear firmly attached to bark
  • Grayish-white to pale coloration
  • Smooth to slightly rough texture
  • Size typically ranging from a few millimeters to a couple of centimeters across
  • Often found alongside other lichen species on the same tree

Remember, lichens grow very slowly, so don’t expect to see dramatic changes from season to season. What you’re seeing may have been developing for years!

Should You Encourage or Remove It?

The short answer? Leave it alone and celebrate its presence! Mycoglaena canadensis and other lichens are completely harmless to trees and actually indicate a healthy environment. Attempting to remove lichens can damage tree bark and is completely unnecessary.

If you want to encourage more lichen diversity in your garden, the best approach is to:

  • Maintain good air quality by avoiding excessive use of chemicals
  • Plant a variety of native trees with different bark textures
  • Avoid pressure washing or scraping tree bark
  • Keep your garden pesticide-free when possible

The Bottom Line

While you can’t exactly plant Mycoglaena canadensis like you would a flower or shrub, discovering it in your garden is like finding a tiny certificate of environmental approval. This humble lichen is quietly doing its part to indicate clean air and contribute to your garden’s ecosystem. So the next time you’re out examining your trees, take a moment to appreciate these small but significant signs of a healthy, thriving garden environment!

Mycoglaena Canadensis

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Uncertain Ascomycota Class

Subclass
Order

Uncertain Ascomycota Order

Family

Uncertain Ascomycota Family

Genus

Mycoglaena Hohnel - mycoglaena

Species

Mycoglaena canadensis (Ellis & Everh.) Bar

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