North America Native Plant

Oncophorus Moss

Botanical name: Oncophorus raui

USDA symbol: ONRA

Habit: nonvascular

Native status: Native to North America  

Synonyms: Symblepharis raui (Austin) R.S. Williams (SYRA4)   

Oncophorus Moss: A Rare North American Treasure Worth Knowing Have you ever wondered about those tiny green carpets that quietly thrive in the shadowy corners of our natural world? Meet oncophorus moss (Oncophorus raui), a fascinating little bryophyte that’s more special than you might think. This isn’t your garden-variety moss ...

Rare plant alert!

Region: Conservation status by state

Status: S3: Status is uncertain but is somewhere between the following rankings: 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 ⚘

Oncophorus Moss: A Rare North American Treasure Worth Knowing

Have you ever wondered about those tiny green carpets that quietly thrive in the shadowy corners of our natural world? Meet oncophorus moss (Oncophorus raui), a fascinating little bryophyte that’s more special than you might think. This isn’t your garden-variety moss – it’s actually a rare native treasure that deserves our attention and respect.

What Exactly Is Oncophorus Moss?

Oncophorus moss belongs to the wonderful world of bryophytes – those ancient, non-flowering plants that include mosses, liverworts, and hornworts. Think of them as nature’s original ground cover, having been around for hundreds of millions of years before flowering plants even existed!

This particular moss is a terrestrial species, meaning it grows on land rather than in water. Like many of its mossy relatives, oncophorus moss tends to attach itself to solid surfaces like rocks, fallen logs, or tree bark rather than growing directly in soil. It’s always herbaceous (non-woody) and maintains its green color year-round in suitable conditions.

A Rare North American Native

Here’s where things get interesting – and a bit concerning. Oncophorus moss is native to North America, but it’s not exactly common. In fact, it has a Global Conservation Status of S3, which means it’s considered Vulnerable. This classification indicates that the species is either very rare throughout its range or found only in restricted areas, making it susceptible to disappearing entirely.

Scientists estimate there are typically only 21 to 100 occurrences of this moss species, with somewhere between 3,000 and 10,000 individual plants in existence. That’s pretty remarkable when you think about it – you could potentially be looking at one of nature’s more exclusive club members!

Unfortunately, specific information about its geographical distribution within North America isn’t well-documented, which is often the case with rare moss species.

Spotting Oncophorus Moss in the Wild

If you’re lucky enough to encounter oncophorus moss during your outdoor adventures, you’ll want to look for its characteristic growth pattern. Like other mosses in its family, it forms small, dense patches or cushions. You’re most likely to find it growing on:

  • Rock surfaces, especially in shaded areas
  • Fallen logs and decaying wood
  • Tree bark, particularly on the north-facing sides
  • Other solid substrates in moist, protected environments

The moss maintains its green color throughout the year, though it may appear more vibrant during wet seasons and somewhat dormant during dry periods.

Is Oncophorus Moss Beneficial for Gardens?

While oncophorus moss can certainly contribute to the ecological health of natural areas, it’s not really a species you’d intentionally cultivate in your garden. Here’s why:

Its rarity makes it unsuitable for garden use. Given its vulnerable conservation status, this moss should be left undisturbed in its natural habitat. Collecting or transplanting wild specimens would be environmentally irresponsible and could further threaten the species.

Additionally, like most specialized mosses, oncophorus moss likely has very specific environmental requirements that would be difficult to replicate in typical garden settings. It has evolved to thrive in particular microhabitats that provide just the right combination of moisture, light, and substrate conditions.

What This Means for Nature Lovers

If you’re passionate about supporting native biodiversity, the best thing you can do for oncophorus moss is to:

  • Learn to identify and appreciate it in its natural habitat
  • Avoid disturbing areas where you find it growing
  • Support conservation efforts that protect the ecosystems where rare mosses thrive
  • Consider cultivating other, more common native moss species in your garden instead

Remember, not every native plant is meant for our gardens, and that’s perfectly okay! Sometimes the most meaningful way to connect with native species is simply to observe and protect them where they naturally belong.

The Bigger Picture

Oncophorus moss might be small and easily overlooked, but it’s part of North America’s rich botanical heritage. These tiny plants play important roles in their ecosystems, helping to prevent soil erosion, providing microhabitats for even smaller organisms, and contributing to the overall health of forest communities.

So the next time you’re hiking through North American forests, keep an eye out for the subtle beauty of mosses like Oncophorus raui. While you might not bring them home to your garden, you can certainly bring home a greater appreciation for the incredible diversity of our native plant communities – including the rare and wonderful ones that prefer to remain wild.

Oncophorus Moss

Classification

Group

Moss

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Bryophyta - Mosses

Subdivision

Musci

Class

Bryopsida - True mosses

Subclass

Bryidae

Order

Dicranales

Family

Dicranaceae Schimp.

Genus

Oncophorus (Brid.) Brid. - oncophorus moss

Species

Oncophorus raui (Austin) Grout - oncophorus moss

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