North America Native Plant

Brouard’s Rim Lichen

Botanical name: Lecanora brouardii

USDA symbol: LEBR5

Habit: lichen

Native status: Native to North America  

Synonyms: Parmularia brouardii de Lesd. (PABR9)   

Brouard’s Rim Lichen: A Tiny Natural Wonder Worth Knowing Have you ever noticed those colorful, crusty patches growing on rocks and wondered what they were? You might have been looking at a lichen! Today, we’re diving into the fascinating world of Brouard’s rim lichen (Lecanora brouardii), a native North American ...

Brouard’s Rim Lichen: A Tiny Natural Wonder Worth Knowing

Have you ever noticed those colorful, crusty patches growing on rocks and wondered what they were? You might have been looking at a lichen! Today, we’re diving into the fascinating world of Brouard’s rim lichen (Lecanora brouardii), a native North American species that’s more interesting than you might think.

What Exactly is Brouard’s Rim Lichen?

Brouard’s rim lichen isn’t actually a plant at all – it’s something much more remarkable. This little organism is actually two life forms living together in perfect harmony: a fungus and an algae. This partnership, called symbiosis, allows them to thrive in places where neither could survive alone. The fungus provides structure and protection, while the algae produces food through photosynthesis. Pretty neat, right?

You might also see this species referred to by its scientific synonym, Parmularia brouardii, but Lecanora brouardii is the currently accepted name.

Where to Find This Native Beauty

As a native species to North America, Brouard’s rim lichen has been quietly doing its thing on our continent for ages. While specific distribution details are limited, like most rim lichens, it typically makes its home on rock surfaces in natural areas.

Is it Beneficial to Your Garden?

Here’s where things get interesting! While you can’t exactly plant Brouard’s rim lichen like you would a flower, having lichens around your garden is actually a wonderful sign. Lichens are incredibly sensitive to air pollution, so their presence indicates that your local air quality is pretty good – think of them as nature’s air quality monitors!

If you have natural stone features, rock walls, or boulder gardens, you might be lucky enough to have lichens colonize these surfaces naturally over time. This process happens very slowly (we’re talking years to decades), but the wait is worth it for these living jewels.

How to Identify Brouard’s Rim Lichen

Identifying specific lichen species can be tricky, even for experts, but here are some general characteristics to look for:

  • Forms thin, crusty patches on rock surfaces
  • Typically has a rim or border around the edges (hence the rim lichen name)
  • Colors can vary but often appear grayish, whitish, or pale
  • Grows very slowly and stays relatively small
  • Feels rough or crusty to the touch

Creating Lichen-Friendly Spaces

While you can’t plant lichens directly, you can create conditions that might encourage them to appear naturally:

  • Include natural stone elements like rock gardens or stone walls
  • Avoid using chemical treatments near potential lichen habitat
  • Be patient – lichen establishment takes years
  • Maintain good air quality by avoiding pollutants when possible

A Living Indicator of Environmental Health

Perhaps the most valuable thing about Brouard’s rim lichen and its relatives is what their presence tells us about our environment. These sensitive organisms can’t tolerate poor air quality, so finding them in your area is like getting a gold star for environmental health!

Next time you’re out exploring rocky areas or examining stone features in natural settings, take a moment to appreciate these remarkable partnerships between fungi and algae. Brouard’s rim lichen might be small and slow-growing, but it’s part of a fascinating world of organisms that have mastered the art of cooperation – and that’s something worth celebrating in any garden or natural space.

Brouard’s Rim Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Lecanoraceae Körb.

Genus

Lecanora Ach. - rim lichen

Species

Lecanora brouardii (de Lesd.) ined.? - Brouard's rim lichen

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