North America Native Plant

Lecidella Lichen

Botanical name: Lecidella viridans

USDA symbol: LEVI18

Habit: lichen

Native status: Native to North America  

Synonyms: Lecidea viridans (Flotow) Lamy (LEVI19)   

Lecidella Lichen: The Tiny Green Garden Helper You Never Knew You Had Have you ever noticed small, crusty greenish patches on tree bark or rocks in your garden and wondered what they were? Meet lecidella lichen (Lecidella viridans), a fascinating organism that’s probably been quietly living in your outdoor space ...

Lecidella Lichen: The Tiny Green Garden Helper You Never Knew You Had

Have you ever noticed small, crusty greenish patches on tree bark or rocks in your garden and wondered what they were? Meet lecidella lichen (Lecidella viridans), a fascinating organism that’s probably been quietly living in your outdoor space all along! This native North American species might look insignificant, but it’s actually playing an important role in your garden’s ecosystem.

What Exactly Is Lecidella Lichen?

First things first – lecidella lichen isn’t actually a plant at all! It’s a lichen, which is a unique partnership between a fungus and algae working together in perfect harmony. Think of it as nature’s ultimate roommate situation, where both parties benefit from the arrangement. The fungus provides structure and protection, while the algae produces food through photosynthesis.

Lecidella viridans appears as small, crusty patches that range from pale green to grayish-green in color. These patches typically measure just a few millimeters across, making them easy to overlook unless you’re really paying attention.

Where You’ll Find This Native Beauty

This lichen is native to North America and can be found across temperate regions of the continent. It’s particularly fond of settling on tree bark and rock surfaces, where it forms those characteristic crusty patches. You might spot it on oak trees, maples, or even on stone walls and boulders in your garden.

Is Lecidella Lichen Good for Your Garden?

Absolutely! While you can’t plant lecidella lichen like you would a flower or shrub, its presence in your garden is actually a wonderful sign. Here’s why you should be happy to see it:

  • It’s an excellent indicator of good air quality – lichens are sensitive to pollution, so their presence means your garden air is clean
  • It doesn’t harm trees or rocks; it simply uses them as a place to live
  • It contributes to biodiversity by providing habitat for tiny insects and other microorganisms
  • It helps with nutrient cycling by slowly breaking down organic matter

How to Identify Lecidella Lichen

Spotting lecidella lichen is like going on a tiny treasure hunt in your own backyard! Here’s what to look for:

  • Color: Greenish-gray to pale green crusty patches
  • Texture: Crusty or granular appearance, not smooth
  • Size: Small patches, usually just a few millimeters across
  • Location: On tree bark (especially hardwoods) and rock surfaces
  • Growth pattern: Forms irregular, roughly circular patches

Creating a Lichen-Friendly Environment

While you can’t plant lecidella lichen, you can certainly encourage its natural establishment in your garden:

  • Avoid using chemical pesticides and fertilizers, which can harm these sensitive organisms
  • Maintain good air quality around your property
  • Leave natural surfaces like tree bark and rocks undisturbed
  • Avoid pressure washing trees or scrubbing rocks where lichens might grow
  • Be patient – lichens grow very slowly, sometimes taking years to establish visible colonies

A Living Indicator of Garden Health

Think of lecidella lichen as your garden’s natural air quality monitor. Its presence tells you that your outdoor space is healthy and unpolluted – something that benefits not just the lichen, but all the plants, animals, and people who spend time there.

So the next time you’re wandering through your garden, take a moment to appreciate these tiny, crusty patches. They might not be showy like your roses or dramatic like your hostas, but lecidella lichen represents the quiet, essential work that nature does every day to keep our ecosystems balanced and healthy.

Lecidella Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Lecanoraceae Körb.

Genus

Lecidella Körb. - lecidella lichen

Species

Lecidella viridans (Flotow) Körb. - lecidella lichen

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