North America Native Plant

Moxley’s Dry Rock Moss

Botanical name: Grimmia moxleyi

USDA symbol: GRMO6

Habit: nonvascular

Native status: Native to North America  

Discovering Moxley’s Dry Rock Moss: A Hidden Gem in North America’s Natural Landscape Have you ever wondered about those tiny green carpets clinging to rocks during your nature walks? Meet Moxley’s dry rock moss (Grimmia moxleyi), a fascinating little bryophyte that’s been quietly doing its thing across North America for ...

Rare plant alert!

Region: Conservation status by state

Status: S2S4: Status is uncertain but is somewhere between the following rankings: Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Discovering Moxley’s Dry Rock Moss: A Hidden Gem in North America’s Natural Landscape

Have you ever wondered about those tiny green carpets clinging to rocks during your nature walks? Meet Moxley’s dry rock moss (Grimmia moxleyi), a fascinating little bryophyte that’s been quietly doing its thing across North America for centuries. While you probably won’t find this moss at your local garden center, understanding what it is and why it matters can deepen your appreciation for the intricate world of native plants.

What Exactly is Moxley’s Dry Rock Moss?

Moxley’s dry rock moss belongs to the diverse world of bryophytes – those ancient, non-flowering plants that include mosses, liverworts, and hornworts. Unlike the showy perennials in your flower beds, this moss is decidedly understated. It’s a terrestrial species that prefers to make its home on solid surfaces like rocks, dead wood, or even living tree bark, rather than settling into soil like most plants we’re familiar with.

As its common name suggests, this moss has adapted to drier conditions than many of its moisture-loving cousins. It forms small, cushion-like patches that can weather dry spells remarkably well – a trait that’s earned it a spot in the dry rock moss category.

Where You Might Spot This Native Beauty

This moss is a true North American native, though its exact distribution patterns aren’t well-documented in popular gardening resources. Like many bryophytes, it tends to fly under the radar of casual plant enthusiasts, known primarily to bryologists (moss specialists) and dedicated naturalists.

Is Moxley’s Dry Rock Moss Beneficial for Gardens?

While you’re unlikely to deliberately cultivate this moss, it can be quite beneficial when it appears naturally:

  • It helps prevent soil erosion on rocky surfaces and slopes
  • Provides microhabitat for tiny insects and other small creatures
  • Adds subtle textural interest to rock gardens and natural areas
  • Requires absolutely no maintenance – it’s the ultimate low-care plant
  • Indicates healthy, unpolluted air quality in your area

A Word About Conservation

Here’s where things get interesting – and important. Moxley’s dry rock moss has a conservation status of S2S4, which suggests it may be uncommon to fairly common depending on the location. This means if you’re lucky enough to discover it growing naturally on your property, you should consider yourself a steward of something special.

Rather than trying to transplant or disturb natural colonies, the best approach is to simply appreciate and protect what’s already there. Avoid using pesticides or fertilizers near areas where you’ve spotted native mosses, and be mindful not to damage rock surfaces where they’re growing.

How to Identify This Moss

Identifying specific moss species can be tricky without a hand lens and some serious bryological knowledge. However, if you spot small, cushion-forming moss on dry rocks or bark, particularly in areas that seem to dry out between rain events, you might be looking at a Grimmia species. The exact identification of Moxley’s dry rock moss would require microscopic examination of features like leaf shape and spore characteristics – definitely a job for the experts!

The Bigger Picture

While Moxley’s dry rock moss might not be the star of your garden show, it represents something valuable: the incredible diversity of native plants that exist right under our noses. These small, humble species play important ecological roles and connect us to the complex web of life that makes healthy ecosystems possible.

Next time you’re out exploring rocky areas, take a moment to appreciate the tiny green worlds clinging to stone surfaces. You might just be looking at Moxley’s dry rock moss – a small but significant piece of North America’s natural heritage.

Moxley’s Dry Rock Moss

Classification

Group

Moss

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Bryophyta - Mosses

Subdivision

Musci

Class

Bryopsida - True mosses

Subclass

Bryidae

Order

Grimmiales

Family

Grimmiaceae Arn.

Genus

Grimmia Hedw. - grimmia dry rock moss

Species

Grimmia moxleyi R.S. Williams - Moxley's dry rock moss

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