North America Native Plant

Ammons’ Tortula Moss

Botanical name: Tortula ammonsiana

USDA symbol: TOAM3

Habit: nonvascular

Native status: Native to North America  

Ammons’ Tortula Moss: A Rare Native Bryophyte Worth Knowing If you’ve ever taken a close look at the tiny green carpets growing on rocks or tree bark in your garden, you might have encountered one of nature’s most underappreciated plants: moss. Today, let’s explore Ammons’ tortula moss (Tortula ammonsiana), a ...

Rare plant alert!

Region: Conservation status by state

Status: S1S3: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Ammons’ Tortula Moss: A Rare Native Bryophyte Worth Knowing

If you’ve ever taken a close look at the tiny green carpets growing on rocks or tree bark in your garden, you might have encountered one of nature’s most underappreciated plants: moss. Today, let’s explore Ammons’ tortula moss (Tortula ammonsiana), a fascinating native species that plays a quiet but important role in North American ecosystems.

What Exactly Is Ammons’ Tortula Moss?

Ammons’ tortula moss is a bryophyte – that’s the fancy scientific term for the group that includes mosses, liverworts, and hornworts. These ancient plants have been around for hundreds of millions of years, making them some of Earth’s botanical old-timers. Unlike the flowering plants we typically think of when gardening, mosses are non-vascular plants that absorb water and nutrients directly through their leaves.

This particular species is a terrestrial moss, meaning it grows on land rather than in water. You’ll typically find it forming small cushions or mats on various surfaces like rocks, soil, tree bark, or even old wooden structures. It’s herbaceous in nature, staying green and relatively soft throughout its growing season.

Where Does This Moss Call Home?

Tortula ammonsiana is native to North America, though specific details about its exact geographic distribution are limited in available research. Like many moss species, it likely has a patchy distribution across suitable habitats within its native range.

A Word of Caution: Rarity Matters

Here’s something important to know: Ammons’ tortula moss has a Global Conservation Status of S1S3, which indicates it’s considered rare and potentially vulnerable. This means that wild populations are limited and deserve our protection. If you’re lucky enough to spot this moss in nature, it’s best to observe and appreciate it from a distance rather than collecting it.

Is This Moss Beneficial in Gardens?

While you shouldn’t actively collect wild specimens due to its rarity, understanding the role of native mosses like Tortula ammonsiana can help you appreciate the small-scale ecosystems in your garden. Mosses provide several benefits:

  • Create microhabitats for tiny invertebrates and soil organisms
  • Help prevent soil erosion with their mat-like growth
  • Retain moisture in the surrounding area
  • Add textural diversity to natural landscapes
  • Serve as pioneer species, helping establish plant communities on bare surfaces

How to Identify Ammons’ Tortula Moss

Identifying specific moss species can be tricky even for experts, but here are some general characteristics to look for if you suspect you’ve found a Tortula species:

  • Small, cushion-forming or mat-like growth pattern
  • Tiny leaves arranged in a spiral pattern around the stem
  • Often found growing on rocks, soil, or bark
  • Green to yellowish-green coloration when moist
  • May appear more brownish when dry

Keep in mind that definitive identification of moss species often requires microscopic examination of leaf and spore characteristics, so consider reaching out to local botanists or mycological societies if you’re curious about the mosses in your area.

The Bigger Picture

While Ammons’ tortula moss might not be the showstopper plant you’d typically choose for a garden centerpiece, it represents the incredible diversity of native plants that contribute to healthy ecosystems. These small but mighty plants remind us that every organism, no matter how tiny, has a role to play in the web of life.

Instead of trying to cultivate this rare species, consider creating conditions in your garden that support native moss communities in general. This might include maintaining some shaded, moist areas with rocks or logs where mosses can naturally establish themselves.

Respecting Our Rare Native Species

The story of Ammons’ tortula moss is ultimately one of conservation and appreciation. As gardeners and nature enthusiasts, we have the opportunity to protect rare species like this one by leaving wild populations undisturbed and supporting habitat conservation efforts in our communities.

Next time you’re wandering through your garden or local natural areas, take a moment to appreciate the small green worlds growing quietly around us. These ancient plants have survived ice ages and continental shifts – they deserve our respect and protection as we work to create more sustainable and biodiverse landscapes.

Ammons’ Tortula Moss

Classification

Group

Moss

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Bryophyta - Mosses

Subdivision

Musci

Class

Bryopsida - True mosses

Subclass

Bryidae

Order

Pottiales

Family

Pottiaceae Hampe

Genus

Tortula Hedw. - tortula moss

Species

Tortula ammonsiana H.A. Crum & L.E. Anderson - Ammons' tortula moss

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