North America Native Plant

Obsolete Polyblastia Lichen

Botanical name: Polyblastia obsoleta

USDA symbol: POOB5

Habit: lichen

Native status: Native to North America  

Obsolete Polyblastia Lichen: A Tiny Garden Visitor You Might Never Notice Have you ever taken a close look at the seemingly bare surfaces in your garden and wondered if there’s more life there than meets the eye? Enter the obsolete polyblastia lichen (Polyblastia obsoleta), a fascinating little organism that’s probably ...

Obsolete Polyblastia Lichen: A Tiny Garden Visitor You Might Never Notice

Have you ever taken a close look at the seemingly bare surfaces in your garden and wondered if there’s more life there than meets the eye? Enter the obsolete polyblastia lichen (Polyblastia obsoleta), a fascinating little organism that’s probably been quietly living in your outdoor space without you even knowing it!

What Exactly Is Obsolete Polyblastia Lichen?

Despite its name suggesting something outdated, the obsolete polyblastia lichen is very much alive and thriving. This tiny organism belongs to the wonderful world of lichens – those remarkable partnerships between fungi and algae that create some of nature’s most resilient life forms.

Polyblastia obsoleta appears as a thin, grayish crust that forms on various surfaces. It’s what scientists call a crustose lichen, meaning it grows flat against its host surface like a living paint job. You won’t find this little guy putting on a flashy display – it’s more of a subtle, understated presence in the natural world.

Where You’ll Find This Native North American

This lichen is a true North American native, quietly making its home across temperate regions of the continent. You might spot it (if you look very closely!) on tree bark, rocks, or other stable surfaces where it can settle in for the long haul.

Is It Good for Your Garden?

While you can’t exactly plant obsolete polyblastia lichen in your garden beds like you would a tomato or rose bush, its presence is actually a wonderful sign! Here’s why having lichens like this one around is beneficial:

  • They serve as natural air quality indicators – lichens are sensitive to pollution, so their presence suggests cleaner air
  • They contribute to the overall biodiversity of your garden ecosystem
  • They help break down surfaces over time, contributing to soil formation
  • They provide microscopic habitat for tiny creatures you’ll never see

How to Spot Obsolete Polyblastia Lichen

Identifying this lichen requires a bit of detective work and possibly a magnifying glass! Look for:

  • Thin, grayish crusty patches on bark or rock surfaces
  • A texture that looks almost like someone lightly dusted the surface with gray powder
  • Small, dark spots (these are the reproductive structures) embedded in the crusty surface
  • Growth that follows the contours of whatever surface it’s living on

Can You Grow It?

Here’s where things get interesting – you can’t actually cultivate obsolete polyblastia lichen like a traditional garden plant. Lichens are incredibly particular about their growing conditions and simply won’t establish where they don’t want to be. They need the right combination of air quality, moisture, substrate, and environmental conditions that can take years or even decades to develop.

The best thing you can do to encourage lichens in your garden is to:

  • Maintain good air quality around your property
  • Avoid using harsh chemicals or pressure washing surfaces where lichens might grow
  • Leave some natural, undisturbed areas in your landscape
  • Be patient – lichens operate on their own timeline!

The Bottom Line

While obsolete polyblastia lichen might not win any garden beauty contests or attract butterflies to your yard, it’s a quietly important part of North America’s natural heritage. If you discover it growing in your garden, consider yourself lucky to be hosting this ancient partnership between fungus and algae. It’s a small reminder that nature is far more complex and interconnected than we often realize – sometimes the most important garden residents are the ones we barely notice!

Obsolete Polyblastia Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Verrucariales

Family

Verrucariaceae Eschw.

Genus

Polyblastia A. Massal. - polyblastia lichen

Species

Polyblastia obsoleta Arnold - obsolete polyblastia lichen

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