North America Native Plant

Ravenel’s Dot Lichen

Botanical name: Arthonia ravenelii

USDA symbol: ARRA5

Habit: lichen

Native status: Native to North America  

Ravenel’s Dot Lichen: A Tiny Garden Guest You Never Invited (But Should Welcome) Have you ever noticed tiny dark spots scattered across the bark of trees in your garden? Meet Ravenel’s dot lichen (Arthonia ravenelii), one of nature’s most understated residents that might already be living rent-free on your trees ...

Ravenel’s Dot Lichen: A Tiny Garden Guest You Never Invited (But Should Welcome)

Have you ever noticed tiny dark spots scattered across the bark of trees in your garden? Meet Ravenel’s dot lichen (Arthonia ravenelii), one of nature’s most understated residents that might already be living rent-free on your trees – and that’s actually a good thing!

What Exactly Is Ravenel’s Dot Lichen?

Despite its name suggesting it’s a plant, Ravenel’s dot lichen is actually a fascinating partnership between a fungus and an algae (and sometimes a cyanobacterium too). This collaborative relationship, called symbiosis, creates what we see as a lichen – essentially nature’s original roommate success story.

Arthonia ravenelii belongs to the crustose lichen family, meaning it forms a thin, crusty layer that’s tightly bonded to whatever surface it calls home – usually tree bark. Think of it as nature’s living wallpaper, but much more interesting.

Where You’ll Find This Tiny Wonder

This native North American lichen has made itself at home primarily throughout the southeastern United States. It’s particularly fond of the warm, humid conditions found in this region, where it quietly goes about its business on the bark of various trees.

Spotting Ravenel’s Dot Lichen in Your Garden

Identifying this lichen requires a bit of detective work, as it’s not exactly shouting for attention. Here’s what to look for:

  • Small, dark, dot-like structures (called apothecia) scattered across tree bark
  • A thin, often barely visible crusty base layer on the bark surface
  • Typically found on the bark of deciduous trees
  • More common in areas with good air quality and humidity

You’ll need to look closely – these lichens are masters of the understated aesthetic, preferring subtle elegance over flashy displays.

Is It Beneficial to Have in Your Garden?

Absolutely! While you can’t exactly plant or cultivate Ravenel’s dot lichen (it does its own thing, thank you very much), having it appear naturally in your garden is actually a wonderful sign. Here’s why you should celebrate these tiny tenants:

  • Air quality indicator: Lichens are sensitive to air pollution, so their presence suggests you have relatively clean air
  • Ecosystem health: They contribute to biodiversity and indicate a healthy, balanced environment
  • No harm to trees: Despite living on bark, they don’t damage or parasitize their host trees
  • Natural beauty: They add subtle texture and interest to tree bark for those who appreciate nature’s finer details

The Hands-Off Approach to Growing Lichens

Here’s the thing about Ravenel’s dot lichen – you can’t really grow it in the traditional gardening sense. It’s not available at nurseries, you can’t sow seeds, and there’s no watering schedule to follow. Instead, this lichen will find you if conditions are right.

What you can do is create an environment where lichens might naturally establish:

  • Maintain good air quality around your property
  • Avoid using harsh chemicals or fungicides near trees
  • Keep mature trees healthy, as lichens prefer established bark surfaces
  • Allow for natural humidity and air circulation

A Garden Guest Worth Appreciating

While Ravenel’s dot lichen might not win any awards for showiness, it represents something special – a thriving, complex ecosystem right in your backyard. These tiny organisms have been quietly doing their thing for millions of years, long before we started worrying about garden design and plant combinations.

So the next time you’re strolling through your garden, take a moment to appreciate the small dark dots on your tree bark. They’re not just random spots – they’re living proof that your garden is healthy enough to support some of nature’s most fascinating partnerships. And really, isn’t that the kind of garden guest we all want?

Ravenel’s Dot Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Arthoniales

Family

Arthoniaceae Rchb.

Genus

Arthonia Ach. - dot lichen

Species

Arthonia ravenelii Tuck. - Ravenel's dot lichen

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