North America Native Plant

Pammell’s Dotted Lichen

Botanical name: Bacidia pammellii

USDA symbol: BAPA5

Habit: lichen

Native status: Native to North America  

Pammell’s Dotted Lichen: A Tiny Natural Wonder in Your Backyard Have you ever noticed those peculiar crusty patches with tiny black dots scattered across tree bark in your yard? You might be looking at Pammell’s dotted lichen (Bacidia pammellii), a fascinating little organism that’s more complex than it appears. Don’t ...

Pammell’s Dotted Lichen: A Tiny Natural Wonder in Your Backyard

Have you ever noticed those peculiar crusty patches with tiny black dots scattered across tree bark in your yard? You might be looking at Pammell’s dotted lichen (Bacidia pammellii), a fascinating little organism that’s more complex than it appears. Don’t worry if you’ve never heard of it – this unassuming lichen tends to fly under the radar, but it’s actually quite remarkable!

What Exactly Is Pammell’s Dotted Lichen?

First things first: lichens aren’t plants at all! They’re actually a partnership between a fungus and an algae (or sometimes cyanobacteria), living together in perfect harmony. Think of it as nature’s ultimate roommate situation – the fungus provides structure and protection, while the algae makes food through photosynthesis. Pretty cool, right?

Pammell’s dotted lichen is native to North America and belongs to a group of lichens that love making themselves at home on tree bark. Unlike the flowering plants we typically think about when gardening, these little guys have been quietly doing their thing for millions of years.

Where You’ll Find This Native Lichen

This lichen calls North America home, particularly thriving in eastern regions where it can find suitable host trees. You won’t find it at your local nursery (and that’s perfectly normal!), but you might discover it growing naturally on the bark of deciduous trees in woodlands, parks, or even in your own backyard.

Identifying Pammell’s Dotted Lichen

Spotting this lichen is like playing nature’s version of connect-the-dots! Here’s what to look for:

  • A crusty, whitish to pale gray surface that looks almost painted onto the bark
  • Small, distinctive black dots (called perithecia) scattered across the surface
  • A relatively thin, closely attached growth pattern on tree bark
  • Typically found on the smooth bark of deciduous trees

The black dots are actually the lichen’s reproductive structures – think of them as tiny spore-producing factories that help the lichen spread to new locations.

Is It Beneficial to Have in Your Garden?

Absolutely! While you can’t plant or cultivate Pammell’s dotted lichen (it does its own thing, thank you very much), having it appear naturally in your landscape is actually a good sign. Here’s why you should celebrate finding it:

  • It indicates good air quality – lichens are sensitive to pollution and won’t thrive in heavily polluted areas
  • It adds biodiversity to your yard’s ecosystem
  • It doesn’t harm the trees it grows on – it’s just using them as a surface to live on
  • It contributes to the complex web of life that makes healthy ecosystems tick

What This Means for Your Gardening

If you’re lucky enough to spot Pammell’s dotted lichen in your yard, the best thing you can do is… absolutely nothing! This isn’t a plant you can buy, plant, or tend to. Instead, consider it a natural bonus that comes with having mature trees and clean air.

The presence of lichens like this one suggests you’re doing something right with your landscape. Keep maintaining those trees, avoid using harsh chemicals near them, and enjoy knowing that your little patch of earth is supporting some of nature’s most ancient partnerships.

So next time you’re out in your garden, take a moment to look up at your trees. You might just discover you’ve been hosting this remarkable little organism all along – and that’s pretty special!

Pammell’s Dotted Lichen

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 pammellii (Fink) Zahlbr. - Pammell's dotted lichen

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