North America Native Plant

Crater Lichen

Botanical name: Diploschistes muscorum muscorum

USDA symbol: DIMUM

Habit: lichen

Native status: Native to North America  

Synonyms: Diploschistes bryophilus (Ehrh. ex Ach.) Zahlbr. (DIBR7)  ⚘  Diploschistes canadensis Rasanen (DICA23)   

Crater Lichen: A Fascinating Natural Indicator in Your Garden Have you ever noticed small, crusty gray patches dotting the soil or rocks in your garden? You might be looking at crater lichen (Diploschistes muscorum muscorum), a remarkable organism that’s neither plant nor animal, but something wonderfully in between. This native ...

Crater Lichen: A Fascinating Natural Indicator in Your Garden

Have you ever noticed small, crusty gray patches dotting the soil or rocks in your garden? You might be looking at crater lichen (Diploschistes muscorum muscorum), a remarkable organism that’s neither plant nor animal, but something wonderfully in between. This native North American lichen has earned its common name from the distinctive crater-like structures that dot its surface, making it one of the more recognizable lichens you’ll encounter in natural landscapes.

What Exactly Is Crater Lichen?

Crater lichen is a fascinating composite organism made up of a fungus and an alga living together in perfect harmony. This partnership, called symbiosis, allows the lichen to thrive in places where neither partner could survive alone. The fungus provides structure and protection, while the alga produces food through photosynthesis. It’s like nature’s own tiny solar-powered cooperative!

This particular species is native to North America and can be found across temperate regions of the continent. While we don’t have specific distribution maps readily available, crater lichen typically appears wherever conditions are just right for this unique partnership to flourish.

How to Identify Crater Lichen

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

  • Forms crusty, gray to brownish patches on soil, moss, or rock surfaces
  • Features distinctive crater-like structures (called apothecia) that give it its common name
  • Grows in small colonies, often appearing as scattered patches
  • Has a somewhat rough, granular texture when viewed up close
  • Typically measures just a few centimeters across

Is Crater Lichen Beneficial in Your Garden?

While you can’t exactly plant crater 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 spot this little organism:

  • Air quality indicator: Lichens are incredibly sensitive to air pollution, so finding them means your garden has relatively clean air
  • Soil health sign: Their presence often indicates stable, undisturbed soil conditions
  • Ecosystem contribution: They help break down rock and organic matter, contributing to soil formation
  • Low-maintenance beauty: They add subtle texture and interest to natural areas without requiring any care

Where You’ll Find It

Crater lichen isn’t picky about its real estate, but it does have preferences. You’re most likely to encounter it in:

  • Undisturbed garden areas with stable soil
  • Rocky outcrops or stone walls
  • Areas where moss grows over soil
  • Locations with good air circulation and moderate moisture
  • Spots that aren’t regularly disturbed by foot traffic or cultivation

Living with Crater Lichen

The beauty of crater lichen is that it asks for absolutely nothing from you as a gardener. You can’t really grow it in the traditional sense, and honestly, that’s part of its charm. It appears when conditions are right and disappears when they’re not, serving as a natural barometer for your garden’s environmental health.

If you’re lucky enough to have crater lichen in your garden, consider it a badge of honor. It means you’re providing habitat that supports these remarkable organisms. The best thing you can do is simply leave it be and appreciate this small wonder of nature that has chosen to call your garden home.

A Living Partnership Worth Celebrating

Crater lichen reminds us that some of nature’s most interesting inhabitants are also the most humble. While it may not produce showy flowers or dramatic foliage, this quiet partnership between fungus and alga represents millions of years of evolutionary cooperation. Next time you’re wandering through your garden, take a moment to look for these small gray patches – they’re proof that your outdoor space is supporting some of nature’s most fascinating collaborations.

Crater Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Graphidales

Family

Thelotremataceae Stizenb.

Genus

Diploschistes Norman - crater lichen

Species

Diploschistes muscorum (Scop.) R. Sant. - crater lichen

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