North America Native Plant

Zwackhiomyces Arenicola

Botanical name: Zwackhiomyces arenicola

USDA symbol: ZWAR

Habit: lichen

Native status: Native to North America  

Zwackhiomyces arenicola: The Tiny Lichen Parasite You’ll Probably Never Notice Ever heard of Zwackhiomyces arenicola? Don’t worry if you haven’t – this microscopic North American native is one of nature’s more obscure characters. While it might sound like a lichen based on its classification, this little fellow is actually a ...

Zwackhiomyces arenicola: The Tiny Lichen Parasite You’ll Probably Never Notice

Ever heard of Zwackhiomyces arenicola? Don’t worry if you haven’t – this microscopic North American native is one of nature’s more obscure characters. While it might sound like a lichen based on its classification, this little fellow is actually a parasitic fungus that has a very specific lifestyle: it makes its living by growing on other lichens.

What Exactly Is Zwackhiomyces arenicola?

Think of Zwackhiomyces arenicola as nature’s tiny freeloader. This parasitic fungus specifically targets cup lichens (Cladonia species), setting up shop on their surfaces and living off their resources. It’s native to North America and typically found in sandy environments where its host lichens naturally occur.

Unlike the colorful, visible lichens you might spot on tree bark or rocks, this parasitic fungus is so small you’d need a microscope to properly see it. It forms tiny, dark fruiting bodies on the surface of its lichen hosts.

Geographic Distribution

As a North American native, Zwackhiomyces arenicola can be found across various regions of the continent, particularly in sandy coastal areas and other environments where cup lichens thrive. However, specific distribution details remain somewhat mysterious due to its microscopic nature and specialized habitat requirements.

Is It Beneficial to Your Garden?

Here’s the honest truth: Zwackhiomyces arenicola isn’t something you’d actively want or not want in your garden. As a microscopic parasitic fungus, it:

  • Provides no direct aesthetic value
  • Cannot be cultivated or managed like traditional garden plants
  • Has no impact on pollinators or typical garden wildlife
  • Plays a very specialized role in lichen ecology rather than general garden ecosystems

If you do have cup lichens growing naturally in sandy areas of your property, this fungus might already be present as part of the natural ecological balance – and that’s perfectly fine!

How to Identify Zwackhiomyces arenicola

Spotting this tiny parasite requires some detective work:

  • Look for cup lichens (Cladonia species) in sandy areas
  • Examine the lichen surfaces for tiny, dark, pinhead-sized bumps or dots
  • These dark fruiting bodies are typically less than 1mm in diameter
  • A hand lens or magnifying glass will be essential for proper identification
  • For definitive identification, microscopic examination is usually necessary

The Bottom Line

Zwackhiomyces arenicola represents one of nature’s countless specialized relationships that happen right under our noses – or in this case, under our magnifying glasses. While it won’t add beauty to your flower beds or attract butterflies to your yard, it’s a fascinating example of how even the tiniest organisms have found their own unique ecological niches.

If you’re interested in supporting native biodiversity in your landscape, focus on creating habitat for the cup lichens that serve as this fungus’s host. Sandy, well-draining areas with minimal disturbance can naturally support lichen communities, and where lichens thrive, their specialized parasites like Zwackhiomyces arenicola will likely follow.

Zwackhiomyces Arenicola

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Uncertain Ascomycota Class

Subclass
Order

Uncertain Ascomycota Order

Family

Uncertain Ascomycota Family

Genus

Zwackhiomyces Grube & Hafellner - zwackhiomyces lichen

Species

Zwackhiomyces arenicola 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