North America Native Plant

Orthotrichum Moss

Botanical name: Orthotrichum sordidum

USDA symbol: ORSO2

Habit: nonvascular

Native status: Native to North America  

Synonyms: Orthotrichum cancellatum Cardot & Thér. (ORCA10)  ⚘  Orthotrichum microblepharum Schimp. f. rubrum Grout (ORMIR)   

Orthotrichum Moss: A Tiny North American Native Worth Knowing If you’ve ever looked closely at the bark of trees or the surface of rocks and noticed tiny, cushion-like green patches, you might have encountered Orthotrichum sordidum, commonly known as orthotrichum moss. This unassuming little moss is actually a fascinating native ...

Orthotrichum Moss: A Tiny North American Native Worth Knowing

If you’ve ever looked closely at the bark of trees or the surface of rocks and noticed tiny, cushion-like green patches, you might have encountered Orthotrichum sordidum, commonly known as orthotrichum moss. This unassuming little moss is actually a fascinating native North American species that plays a quiet but important role in our natural ecosystems.

What Exactly Is Orthotrichum Moss?

Orthotrichum sordidum belongs to the world of bryophytes – those ancient, non-flowering plants that include mosses, liverworts, and hornworts. Unlike the plants we typically think of for our gardens, this moss doesn’t have roots, flowers, or seeds. Instead, it’s a small, herbaceous plant that forms compact cushions or mats on solid surfaces.

This moss is what scientists call an epiphyte and lithophyte, which is a fancy way of saying it grows on tree bark and rocks rather than in soil. It anchors itself using tiny structures called rhizoids, which work like microscopic grappling hooks.

Where You’ll Find This Native Moss

As a North American native, Orthotrichum sordidum has been quietly making its home across various regions of the continent for thousands of years. You’re most likely to spot it in areas with sufficient humidity, clinging to the bark of deciduous and coniferous trees or settled into the crevices of rocks.

Is Orthotrichum Moss Beneficial for Your Garden?

While you won’t be planting orthotrichum moss in your flower beds anytime soon, its natural presence in your landscape can actually be a positive sign. Here’s why this little moss deserves your appreciation:

  • Environmental indicator: The presence of healthy moss populations often indicates good air quality and appropriate moisture levels
  • Ecosystem support: Mosses provide habitat for tiny invertebrates and help create microhabitats for other small organisms
  • Natural beauty: These small, green cushions add subtle texture and year-round color to tree trunks and rock surfaces
  • Erosion prevention: Moss helps stabilize surfaces and can prevent small-scale erosion

How to Identify Orthotrichum Sordidum

Spotting orthotrichum moss requires getting up close and personal with the natural world. Here are the key features to look for:

  • Size: Very small, forming cushions typically just a few centimeters across
  • Color: Ranges from bright green when moist to brownish-green when dry
  • Texture: Dense, cushion-like growth pattern
  • Location: Found on tree bark, rocks, and occasionally on other solid surfaces
  • Habitat: Prefers areas with adequate moisture and some protection from direct sunlight

Appreciating Moss in Your Landscape

Rather than trying to cultivate orthotrichum moss (which isn’t practical for home gardeners), consider creating conditions that welcome native mosses naturally:

  • Maintain areas of your property with natural tree bark and rock surfaces
  • Avoid using harsh chemicals that might harm delicate moss communities
  • Preserve moisture in shaded areas of your landscape
  • Consider leaving some wild spaces where natural processes can unfold

The Bigger Picture

Orthotrichum sordidum might not be the showstopper of your garden, but it represents something valuable: the intricate web of native species that have called North America home long before our manicured landscapes existed. These tiny mosses remind us that biodiversity exists at every scale, from the towering oaks to the microscopic world thriving on their bark.

Next time you’re walking through a wooded area or even around your own property, take a moment to look closely at the tree trunks and rocks around you. You might just spot some orthotrichum moss quietly doing its part to keep our ecosystems healthy and diverse.

Orthotrichum Moss

Classification

Group

Moss

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Bryophyta - Mosses

Subdivision

Musci

Class

Bryopsida - True mosses

Subclass

Bryidae

Order

Orthotrichales

Family

Orthotrichaceae Arn.

Genus

Orthotrichum Hedw. - orthotrichum moss

Species

Orthotrichum sordidum Sull. & Lesq. - orthotrichum moss

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