North America Native Plant

Submersed Wart Lichen

Botanical name: Verrucaria submersella

USDA symbol: VESU3

Habit: lichen

Native status: Native to North America  

Synonyms: Verrucaria submersa Schaerer (VESU5)   

Submersed Wart Lichen: A Hidden Aquatic Treasure in North American Waters Have you ever noticed dark, crusty patches on rocks in streams or ponds and wondered what they might be? You might have stumbled upon submersed wart lichen (Verrucaria submersella), a fascinating organism that’s neither plant nor animal, but something ...

Submersed Wart Lichen: A Hidden Aquatic Treasure in North American Waters

Have you ever noticed dark, crusty patches on rocks in streams or ponds and wondered what they might be? You might have stumbled upon submersed wart lichen (Verrucaria submersella), a fascinating organism that’s neither plant nor animal, but something wonderfully unique in between.

What Exactly Is Submersed Wart Lichen?

Despite its name suggesting it’s a plant, submersed wart lichen is actually a lichen – a remarkable partnership between fungi and algae working together in perfect harmony. This tiny organism forms thin, dark crusts on rocks that spend time underwater or get regularly splashed by freshwater streams, rivers, and ponds.

The scientific name Verrucaria submersella might be a mouthful, but it perfectly describes this little wonder. Verrucaria refers to its warty appearance, while submersella hints at its love for underwater living. You might also see it referred to by its synonym, Verrucaria submersa.

Where Can You Find This Aquatic Lichen?

This native North American species has made itself at home in freshwater environments across the continent. You’ll typically spot submersed wart lichen clinging to rocks in streams, rivers, pond edges, and other freshwater habitats where the water is clean and unpolluted.

Is Submersed Wart Lichen Beneficial for Your Garden?

While you can’t exactly plant submersed wart lichen in your garden bed, its presence in nearby water features is actually fantastic news! Here’s why this little lichen is worth celebrating:

  • It’s a natural indicator of good water quality – polluted water means no lichen
  • It contributes to the aquatic ecosystem’s health and biodiversity
  • It helps stabilize underwater surfaces and prevents erosion
  • It’s part of the natural food web in freshwater environments

If you have a natural pond, stream, or water feature on your property, the presence of submersed wart lichen is like getting a gold star for environmental stewardship!

How to Identify Submersed Wart Lichen

Spotting submersed wart lichen takes a keen eye, but once you know what to look for, you’ll start noticing it everywhere:

  • Look for thin, dark (usually blackish or dark brown) crusty patches on rocks
  • Check rocks that are submerged or regularly wetted by clean freshwater
  • The surface appears somewhat warty or bumpy, hence the wart lichen name
  • It forms tight crusts that seem to be painted directly onto the rock surface
  • You’ll typically find it in areas with good water flow and clean conditions

Supporting Aquatic Lichens in Your Landscape

While you can’t cultivate submersed wart lichen like a traditional garden plant, you can certainly create conditions that welcome it:

  • Maintain clean, unpolluted water sources on your property
  • Avoid using chemicals near streams, ponds, or water features
  • Leave natural rock surfaces undisturbed in aquatic areas
  • Support watershed health through responsible landscaping practices

Remember, lichens like Verrucaria submersella are incredibly sensitive to air and water pollution. Their presence is nature’s way of giving you a thumbs up for maintaining a healthy environment. So next time you’re near a freshwater area, take a moment to appreciate these tiny but mighty organisms – they’re working hard to keep our aquatic ecosystems thriving!

Submersed Wart Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Verrucariales

Family

Verrucariaceae Eschw.

Genus

Verrucaria Schrad. - wart lichen

Species

Verrucaria submersella Servit - submersed wart lichen

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