North America Native Plant

Trichothelium Crocynioides

Botanical name: Trichothelium crocynioides

USDA symbol: TRCR17

Habit: lichen

Native status: Native to North America  

Trichothelium crocynioides: A Mysterious Native Lichen Worth Knowing If you’ve ever wondered about those crusty, colorful patches growing on tree bark or rocks in your garden, you might have encountered a lichen – and possibly even the elusive Trichothelium crocynioides. This native North American lichen represents one of nature’s most ...

Trichothelium crocynioides: A Mysterious Native Lichen Worth Knowing

If you’ve ever wondered about those crusty, colorful patches growing on tree bark or rocks in your garden, you might have encountered a lichen – and possibly even the elusive Trichothelium crocynioides. This native North American lichen represents one of nature’s most fascinating partnerships, though it remains one of the more mysterious members of our continent’s diverse lichen community.

What Exactly Is Trichothelium crocynioides?

Trichothelium crocynioides is a lichen – not a plant in the traditional sense, but rather an amazing collaboration between a fungus and an algae (or sometimes cyanobacteria). Think of it as nature’s ultimate roommate situation: the fungus provides structure and protection, while the algae produces food through photosynthesis. Together, they create something neither could achieve alone.

As a native species to North America, this lichen has been quietly doing its job in our ecosystems long before European settlement, though specific details about its geographic distribution remain somewhat of a botanical mystery.

Is This Lichen Beneficial in Your Garden?

While you can’t exactly plant lichens like you would a tomato or rose bush, having them appear naturally in your garden is actually a wonderful sign! Here’s why lichens like Trichothelium crocynioides can be garden gold:

  • Air quality indicators: Lichens are incredibly sensitive to air pollution, so their presence suggests you have clean air
  • Ecosystem health: They contribute to biodiversity and provide habitat for tiny creatures
  • Natural beauty: They add unique textures and colors to tree bark and surfaces
  • Soil building: Over time, lichens help break down rock and organic matter, contributing to soil formation

How to Identify Trichothelium crocynioides

Here’s where things get tricky – specific identification characteristics for Trichothelium crocynioides aren’t well-documented in accessible sources. Like many lichens, it likely:

  • Grows as a crust-like formation on bark or other surfaces
  • Has a unique combination of colors and textures
  • Requires microscopic examination for definitive identification

If you suspect you’ve found this lichen in your garden, consider reaching out to local mycological societies or university extension programs. Lichen identification often requires specialized knowledge and equipment.

Encouraging Lichens in Your Garden

While you can’t plant lichens directly, you can create conditions that welcome them:

  • Avoid chemical treatments: Skip fungicides and pesticides that might harm these sensitive organisms
  • Maintain mature trees: Lichens often prefer established bark surfaces
  • Reduce air pollution: Support clean air initiatives in your community
  • Practice patience: Lichens grow very slowly, sometimes taking years to establish

The Bottom Line

Trichothelium crocynioides may be one of North America’s more enigmatic lichens, but that doesn’t make it any less valuable to our ecosystems. If you’re lucky enough to spot what might be this species in your garden, consider yourself blessed with a healthy, biodiverse outdoor space. Rather than trying to remove or control lichens, embrace them as living indicators of your garden’s ecological wellness.

Remember, these fascinating organisms have been perfecting their survival strategies for millions of years. Sometimes the best gardening approach is simply to step back and let nature’s partnerships flourish on their own terms.

Trichothelium Crocynioides

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Pyrenulales

Family

Trichotheliaceae Bittner & F. Schill.

Genus

Trichothelium Müll. Arg. - trichothelium lichen

Species

Trichothelium crocynioides R.C. Harris

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