North America Native Plant

Black Pyrenothrix Lichen

Botanical name: Pyrenothrix nigra

USDA symbol: PYNI2

Habit: lichen

Native status: Native to North America  

Synonyms: Lichenothrix riddlei Henssen (LIRI3)   

Black Pyrenothrix Lichen: A Mysterious Native Worth Knowing Ever stumbled across something in your garden that looks like it doesn’t quite belong to the plant world as you know it? Meet the black pyrenothrix lichen (Pyrenothrix nigra), a fascinating organism that’s neither plant nor animal, but something wonderfully unique that ...

Black Pyrenothrix Lichen: A Mysterious Native Worth Knowing

Ever stumbled across something in your garden that looks like it doesn’t quite belong to the plant world as you know it? Meet the black pyrenothrix lichen (Pyrenothrix nigra), a fascinating organism that’s neither plant nor animal, but something wonderfully unique that calls North America home.

What Exactly Is Black Pyrenothrix Lichen?

Before we dive deeper, let’s clear up what we’re looking at here. Black pyrenothrix lichen isn’t actually a plant at all – it’s a lichen! This means it’s a remarkable partnership between a fungus and an algae (or sometimes cyanobacteria) living together in perfect harmony. Think of it as nature’s original roommate situation, where both parties benefit from the arrangement.

You might also see this species referred to by its scientific synonym, Lichenothrix riddlei Henssen, in some older field guides or research papers.

Where You’ll Find This Native Beauty

As a native species to North America, black pyrenothrix lichen has been quietly doing its thing in our ecosystems long before any of us started thinking about native gardening. While specific distribution details for this particular species are limited in readily available sources, it’s part of our continent’s natural heritage.

Is It Beneficial to Your Garden?

Here’s where lichens get really interesting for gardeners! While you won’t be planting black pyrenothrix lichen like you would a wildflower, its presence in your outdoor space can actually be a wonderful sign. Lichens are:

  • Natural air quality indicators – they’re sensitive to pollution, so seeing them suggests cleaner air
  • Part of a healthy ecosystem that supports biodiversity
  • Slow but steady contributors to soil formation as they break down rock surfaces
  • Unique textural elements that add natural character to gardens

How to Identify Black Pyrenothrix Lichen

Spotting black pyrenothrix lichen requires a bit of detective work, as detailed identification characteristics for this specific species aren’t widely documented in popular field guides. However, as its common name suggests, you’ll likely be looking for darker coloration typical of the black descriptor.

General lichen identification tips that might help:

  • Look for crusty, leafy, or branching growth patterns on rocks, tree bark, or other surfaces
  • Notice the color – in this case, darker tones as the name implies
  • Observe where it’s growing – different lichens prefer different substrates
  • Consider the overall size and texture

Living With Lichens in Your Landscape

The best approach to black pyrenothrix lichen is simply to appreciate it when you find it. Unlike traditional garden plants, lichens don’t need our help to thrive – in fact, they prefer we leave them alone! Here’s how to be a good lichen neighbor:

  • Avoid disturbing areas where you spot lichens growing
  • Don’t try to transplant or move them – they’re extremely slow-growing and sensitive
  • Consider their presence a sign of a healthy, balanced outdoor environment
  • Use their appearance as inspiration for creating more naturalistic garden spaces

The Bottom Line

Black pyrenothrix lichen might not be the showstopper you plant for curb appeal, but it’s a quiet testament to the complex, interconnected nature of healthy ecosystems. If you’re lucky enough to spot this native lichen in your outdoor space, take a moment to appreciate this ancient partnership between fungus and algae that’s been perfecting sustainable living long before it was trendy.

Remember, the presence of lichens like Pyrenothrix nigra often indicates that you’re doing something right in creating a space that supports native biodiversity – and that’s something worth celebrating!

Black Pyrenothrix Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Pyrenulales

Family

Pyrenotrichaceae Zahlbr.

Genus

Pyrenothrix Riddle - pyrenothrix lichen

Species

Pyrenothrix nigra Riddle - black pyrenothrix lichen

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