North America Native Plant

Bowl Lichen

Botanical name: Psoroma tenue

USDA symbol: PSTE13

Habit: lichen

Native status: Native to North America  

Bowl Lichen: A Tiny Treasure Hiding in Your Garden Have you ever noticed small, cup-shaped structures scattered across the soil in your garden and wondered what they might be? You could be looking at bowl lichen (Psoroma tenue), one of nature’s most fascinating partnerships that’s quietly contributing to your garden’s ...

Bowl Lichen: A Tiny Treasure Hiding in Your Garden

Have you ever noticed small, cup-shaped structures scattered across the soil in your garden and wondered what they might be? You could be looking at bowl lichen (Psoroma tenue), one of nature’s most fascinating partnerships that’s quietly contributing to your garden’s ecosystem.

What Exactly Is Bowl Lichen?

Bowl lichen isn’t a plant at all – it’s actually a remarkable collaboration between a fungus and an algae living together in perfect harmony. This partnership, called symbiosis, creates what we see as lichen. The fungus provides structure and protection, while the algae produces food through photosynthesis. It’s like nature’s ultimate roommate situation!

Bowl lichen gets its common name from its distinctive appearance. The fruiting bodies (called apothecia) form small, brownish cups or bowls that can be quite charming when you know what to look for.

Where You’ll Find Bowl Lichen

This native North American species has made itself at home across boreal forests and mountainous regions throughout the continent. In your garden, you’re most likely to spot it growing on soil, over moss, or on decaying organic matter in shaded, humid areas.

Identifying Bowl Lichen in Your Garden

Spotting bowl lichen requires a keen eye, as these little guys are quite small. Here’s what to look for:

  • Small, cup or bowl-shaped fruiting bodies
  • Brownish coloration that may vary from light tan to darker brown
  • Size typically ranges from just a few millimeters across
  • Usually found growing on soil or decaying organic matter
  • Prefers shaded, moist areas of your garden

Is Bowl Lichen Beneficial for Your Garden?

While bowl lichen might seem insignificant, it’s actually playing several important roles in your garden ecosystem:

  • Helps break down organic matter, contributing to soil health
  • Indicates good air quality – lichens are sensitive to pollution
  • Provides microscopic habitat for tiny soil organisms
  • May offer nesting materials for some insects
  • Adds to the biodiversity of your garden’s microhabitat

Can You Cultivate Bowl Lichen?

Here’s where bowl lichen differs dramatically from traditional garden plants – you can’t actually grow it on purpose! Lichens require very specific environmental conditions, including the right humidity levels, air quality, and substrate. They also grow extremely slowly, sometimes taking years to establish.

The best approach is to appreciate bowl lichen when it appears naturally in your garden. If you’re finding it in your space, congratulations – it’s a sign that you have a healthy, diverse garden ecosystem!

Creating Lichen-Friendly Conditions

While you can’t plant bowl lichen, you can create conditions that might encourage its natural occurrence:

  • Maintain areas of undisturbed soil and leaf litter
  • Avoid excessive use of fertilizers and pesticides
  • Preserve shaded, humid microclimates in your garden
  • Allow some areas to remain wild and less manicured
  • Keep air quality in mind – lichens hate pollution

The Bottom Line on Bowl Lichen

Bowl lichen represents one of those quiet garden inhabitants that’s easy to overlook but adds real value to your outdoor space. While you won’t be adding it to your shopping list at the garden center, discovering it naturally occurring in your garden is something to celebrate. It’s a sign of ecological health and adds another layer of complexity to your garden’s web of life.

Next time you’re wandering through your garden, take a moment to look down at the soil surface. You might just spot these tiny bowls and gain a new appreciation for the incredible diversity that exists right under our noses!

Bowl Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Pannariaceae Tuck.

Genus

Psoroma Michx. - bowl lichen

Species

Psoroma tenue Henssen - bowl lichen

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