North America Native Plant

Bacidia Vermifera

Botanical name: Bacidia vermifera

USDA symbol: BAVE6

Habit: lichen

Native status: Native to North America  

Synonyms: Bacidia hegetschweileri auct. (BAHE8)   

Bacidia vermifera: The Quiet Crusty Lichen Living on Your Trees Have you ever noticed thin, pale patches spreading across tree bark in your yard and wondered what they were? You might be looking at Bacidia vermifera, a fascinating crustose lichen that’s been quietly making itself at home on North American ...

Bacidia vermifera: The Quiet Crusty Lichen Living on Your Trees

Have you ever noticed thin, pale patches spreading across tree bark in your yard and wondered what they were? You might be looking at Bacidia vermifera, a fascinating crustose lichen that’s been quietly making itself at home on North American trees for centuries. While you can’t plant this curious organism in your garden like a typical flower or shrub, understanding what it is and recognizing its presence can give you valuable insights into your local ecosystem’s health.

What Exactly Is Bacidia vermifera?

Bacidia vermifera isn’t a plant at all – it’s a lichen! If you’re scratching your head wondering what that means, think of lichens as nature’s ultimate roommate situation. They’re actually a partnership between a fungus and an alga (or sometimes a cyanobacterium), working together in perfect harmony. The fungus provides structure and protection, while the alga produces food through photosynthesis. It’s like having a built-in chef and security guard all in one!

This particular lichen species is also known by the synonym Bacidia hegetschweileri, though you’re unlikely to need that tongue-twister for casual conversation. As a crustose lichen, Bacidia vermifera forms thin, crust-like patches that seem almost painted onto tree bark.

Where You’ll Find This Crusty Character

Bacidia vermifera is a true North American native, spreading its pale patches across trees throughout the continent. You’ll find it in temperate regions where mature forests provide the perfect conditions for lichen communities to thrive.

Spotting Bacidia vermifera in the Wild

Identifying this lichen takes a bit of detective work, but it’s worth the effort! Here’s what to look for:

  • Thin, crusty patches on tree bark that look almost like someone dabbed pale paint on the surface
  • Colors ranging from grayish-white to subtle greenish tones
  • A relatively smooth texture that follows the contours of the bark
  • Small, dark fruiting bodies (called apothecia) that may appear as tiny dots scattered across the surface

The easiest way to spot Bacidia vermifera is to examine the bark of mature deciduous trees in your area, particularly in locations with good air quality and moderate humidity.

Is This Lichen Beneficial for Your Garden?

While you can’t cultivate Bacidia vermifera like you would a tomato plant, its presence in your garden or landscape is actually a wonderful sign! Lichens are incredibly sensitive to air pollution, so finding them thriving on your trees means you’re breathing some pretty clean air. Think of them as nature’s air quality monitors – and they work for free!

Here are some benefits of having lichens like Bacidia vermifera around:

  • They indicate good air quality in your area
  • They add subtle natural beauty and texture to tree bark
  • They contribute to biodiversity in forest ecosystems
  • They cause no harm to healthy trees (they’re not parasites!)
  • They help with nutrient cycling in forest environments

Creating Lichen-Friendly Conditions

You can’t plant Bacidia vermifera, but you can create conditions that encourage lichens to naturally colonize your landscape:

  • Maintain mature trees with textured bark
  • Avoid using chemical treatments on tree bark
  • Keep air quality high by reducing pollution sources
  • Allow natural humidity levels around trees
  • Be patient – lichens grow very slowly and may take years to establish

The Bottom Line on Bacidia vermifera

While this crusty lichen won’t add colorful blooms to your garden or attract butterflies to your yard, Bacidia vermifera serves as a quiet testament to your area’s environmental health. Its presence tells you that your local air quality is good enough to support these sensitive organisms, and that’s something worth celebrating!

So the next time you’re walking through your garden or a nearby forest, take a moment to appreciate these humble crusty patches. They may not be showy, but they’re playing an important role in the complex web of life that makes our ecosystems function. And honestly, there’s something pretty amazing about an organism that’s figured out how to make a living by simply hanging out on tree bark, quietly doing its thing year after year.

Bacidia Vermifera

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Bacidiaceae Walt. Watson

Genus

Bacidia De Not. - dotted lichen

Species

Bacidia vermifera (Nyl.) Fr.

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