North America Native Plant

Melanelia Lichen

Botanical name: Melanelia glabroides

USDA symbol: MEGL6

Habit: lichen

Native status: Native to North America  

Synonyms: Parmelia glabroides Essl. (PAGL13)   

Melanelia Lichen: The Crusty Rock Dweller That’s Actually Helping Your Garden If you’ve ever noticed grayish-green, crusty patches growing on rocks, stone walls, or even concrete surfaces in your garden, you’ve likely encountered melanelia lichen (Melanelia glabroides). This fascinating organism isn’t a plant at all, but rather a unique partnership ...

Melanelia Lichen: The Crusty Rock Dweller That’s Actually Helping Your Garden

If you’ve ever noticed grayish-green, crusty patches growing on rocks, stone walls, or even concrete surfaces in your garden, you’ve likely encountered melanelia lichen (Melanelia glabroides). This fascinating organism isn’t a plant at all, but rather a unique partnership between fungi and algae that’s been quietly working behind the scenes to benefit your outdoor space.

What Exactly Is Melanelia Lichen?

Melanelia lichen is a composite organism made up of fungi and photosynthetic partners (usually algae) living together in a mutually beneficial relationship. This remarkable collaboration creates what looks like a crusty, somewhat scaly coating on hard surfaces. You might also see it referred to by its former scientific name, Parmelia glabroides, though botanists have since reclassified it.

Native to North America, this lichen has adapted to thrive across a wide range of climates and conditions, making it a common sight from coast to coast.

Identifying Melanelia Lichen in Your Garden

Spotting melanelia lichen is easier than you might think once you know what to look for:

  • Appears as grayish-green to brownish crusty patches on rock surfaces
  • Has a somewhat scaly or warty texture that feels rough to the touch
  • Typically grows in irregular, spreading patches
  • Most commonly found on exposed stone, concrete walls, or large rocks
  • Tends to be more prominent on surfaces that receive some moisture but aren’t constantly wet

Is Melanelia Lichen Beneficial to Your Garden?

Absolutely! While it might not be the showiest addition to your landscape, melanelia lichen serves several important functions:

  • Air quality indicator: Lichens are notoriously sensitive to air pollution, so their presence indicates relatively clean air in your garden area
  • Ecosystem support: These organisms contribute to the overall health of your garden’s microecosystem
  • Natural character: They add authentic, wild character to rock gardens and naturalistic landscapes
  • Soil building: Over very long periods, lichens help break down rock surfaces, contributing to soil formation

Creating Conditions That Welcome Melanelia Lichen

Unlike traditional plants, you can’t simply plant melanelia lichen from a nursery. Instead, you can create conditions that encourage natural colonization:

  • Maintain good air quality around your property (avoid excessive use of chemicals)
  • Include natural stone elements like rock walls, boulders, or stone pathways
  • Allow some areas to remain undisturbed where lichens can establish naturally
  • Avoid power washing or aggressive cleaning of stone surfaces where you’d like lichens to grow

Living Harmoniously with Melanelia Lichen

The beauty of melanelia lichen lies in its low-maintenance nature. Once established, it requires no care from you whatsoever. In fact, the best thing you can do is simply leave it alone. Avoid scrubbing it off surfaces unless absolutely necessary, as it takes considerable time to reestablish.

If you’re designing a rock garden or naturalistic landscape, consider melanelia lichen a bonus feature that adds authentic wilderness character to your space. Its presence is actually a sign that you’re maintaining a healthy, unpolluted environment – something both you and your garden can appreciate.

The Bottom Line

While you might not actively seek out melanelia lichen for your garden, learning to recognize and appreciate this humble organism can deepen your understanding of the complex ecosystems thriving right in your backyard. Consider it nature’s seal of approval on your garden’s air quality, and let it add its own quiet charm to your outdoor spaces.

Melanelia Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Parmeliaceae F. Berchtold & J. Presl

Genus

Melanelia Essl. - melanelia lichen

Species

Melanelia glabroides (Essl.) Essl. - melanelia lichen

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