Submersed Rimmed Lichen: A Fascinating Aquatic Lichen in North American Waters
Have you ever noticed crusty, grayish patches clinging to rocks along streams, ponds, or lakeshores? You might have discovered the submersed rimmed lichen (Aspicilia submersa), one of nature’s most resilient and fascinating organisms that thrives where few others can survive.
What Exactly Is Submersed Rimmed Lichen?
Despite its name suggesting it’s a plant, submersed rimmed lichen is actually a remarkable partnership between fungi and algae working together as one organism. This unique collaboration, called a lichen, creates something entirely different from either partner alone. The submersed rimmed lichen has adapted to live in one of the most challenging environments – rocks that are regularly underwater and then exposed to air.
As a native species to North America, this lichen plays an important role in aquatic and semi-aquatic ecosystems, quietly doing its work without much fanfare.
Spotting Submersed Rimmed Lichen in the Wild
Identifying this lichen takes a keen eye and the right location. Here’s what to look for:
- Small, crusty patches that form tight mats on rock surfaces
- Grayish to brownish coloration that may appear darker when wet
- Found exclusively on rocks that experience regular submersion in water
- Typically discovered along shorelines of streams, ponds, lakes, and rivers
- Forms distinctive rimmed patterns that give it its common name
The key distinguishing feature is its habitat – if you’re not looking at submerged or periodically submerged rocks, you’re probably not looking at submersed rimmed lichen!
Is It Beneficial to Your Garden?
Here’s where things get interesting – submersed rimmed lichen isn’t something you can plant, grow, or cultivate in a traditional garden setting. Unlike flowering plants or even mosses, lichens have very specific environmental requirements that are nearly impossible to replicate artificially.
However, if you’re fortunate enough to have natural water features on your property with appropriate rocky substrates, you might discover this lichen has already made itself at home. In this case, consider yourself lucky to have such a unique native species sharing your space!
The Role of Lichens in Nature
While submersed rimmed lichen won’t attract pollinators like flowering plants do, it serves important ecological functions:
- Contributes to the breakdown of rock surfaces through slow weathering processes
- Provides habitat for microscopic organisms
- Serves as an indicator of environmental health – lichens are sensitive to pollution
- Adds to the biodiversity of aquatic ecosystems
Why You Can’t Grow It (And Why That’s Okay)
If you’re thinking about adding submersed rimmed lichen to your garden, here’s the reality check: lichens are essentially impossible to cultivate. They require:
- Specific rock substrates with the right mineral composition
- Precise moisture cycles of submersion and exposure
- Clean water free from pollutants
- Natural colonization by both fungal and algal partners
- Years or even decades to establish visible colonies
Instead of trying to grow what can’t be grown, appreciate these remarkable organisms when you encounter them in their natural habitats. They’re living proof that nature finds ways to thrive in the most unlikely places.
A Living Environmental Monitor
One of the coolest things about submersed rimmed lichen is that it acts like nature’s pollution detector. Lichens are incredibly sensitive to air and water quality, so finding healthy populations is actually a good sign that the local environment is relatively clean and healthy.
Next time you’re near a natural water body, take a moment to look for these quiet survivors clinging to the rocks. You’re witnessing one of nature’s most successful partnerships – a living testament to adaptation, resilience, and the incredible diversity of life that calls North America home.
