North America Native Plant

Cololejeunea Setiloba

Botanical name: Cololejeunea setiloba

USDA symbol: COSE18

Habit: nonvascular

Native status: Native to North America  

Cololejeunea setiloba: A Mysterious North American Liverwort If you’ve stumbled upon the name Cololejeunea setiloba, you’ve discovered one of nature’s more elusive characters. This tiny liverwort is part of the fascinating world of bryophytes – those ancient, non-flowering plants that have been quietly carpeting our planet for millions of years. ...

Rare plant alert!

Region: Conservation status by state

Status: S2?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ 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) ⚘

Cololejeunea setiloba: A Mysterious North American Liverwort

If you’ve stumbled upon the name Cololejeunea setiloba, you’ve discovered one of nature’s more elusive characters. This tiny liverwort is part of the fascinating world of bryophytes – those ancient, non-flowering plants that have been quietly carpeting our planet for millions of years. While it may not be the showstopper of your garden, understanding this little green resident can deepen your appreciation for the intricate ecosystems thriving right under our noses.

What Exactly Is Cololejeunea setiloba?

Cololejeunea setiloba is a liverwort, which places it in the same broad family as mosses and hornworts. Think of liverworts as nature’s original ground cover – they’re herbaceous plants that prefer to attach themselves to solid surfaces like rocks, tree bark, or decaying wood rather than growing directly in soil. Unlike the flowering plants we typically associate with gardening, liverworts are incredibly simple organisms that reproduce through spores rather than seeds.

This particular species calls North America home, though specific details about its exact range remain somewhat mysterious. What we do know is that it carries a Global Conservation Status of S2?, which indicates that information about its population and distribution is still being gathered and understood.

Is This Liverwort Beneficial to Your Garden?

While you won’t be planting Cololejeunea setiloba from seed packets anytime soon, discovering it in your garden could actually be a positive sign. Liverworts like this one serve several subtle but important ecological functions:

  • They help prevent soil erosion by creating protective mats on surfaces
  • They contribute to moisture retention in their immediate environment
  • They provide microhabitat for tiny invertebrates and other small creatures
  • They can indicate good air quality, as many bryophytes are sensitive to pollution

How to Identify Cololejeunea setiloba

Here’s where things get tricky – identifying specific liverwort species often requires a magnifying glass and considerable expertise. Liverworts in the Cololejeunea genus are typically very small, forming thin, leafy mats or patches. They’re often found growing on the bark of trees, rocks, or other solid surfaces in moist environments.

If you suspect you’ve found this species, look for:

  • Tiny, scale-like structures growing in flat, overlapping patterns
  • A preference for growing on bark or rock surfaces rather than soil
  • Very small size – often requiring close inspection to notice
  • A green to brownish-green coloration

A Word About Rarity

Given its uncertain conservation status, Cololejeunea setiloba appears to be quite rare or at least poorly documented. If you believe you’ve encountered this species, consider it a special find! Rather than disturbing it, take photos and perhaps contact local botanical experts or your state’s natural heritage program – your observation could contribute valuable data to our understanding of this elusive plant.

The Bigger Picture

While Cololejeunea setiloba may not be destined for your garden center wish list, its presence (or absence) tells us important stories about ecosystem health. These tiny plants are part of the complex web of life that supports the more visible plants and animals we cherish in our landscapes. By learning to notice and appreciate these small wonders, we become better stewards of the complete natural communities in our gardens and wild spaces.

So the next time you’re examining a tree trunk or boulder in your yard, take a moment to look closely at those tiny green patches. You just might be looking at one of North America’s more mysterious botanical residents!

Cololejeunea Setiloba

Classification

Group

Liverwort

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Hepaticophyta - Liverworts

Subdivision

Hepaticae

Class

Hepaticopsida

Subclass

Jungermanniae

Order

Jungermanniales

Family

Lejeuneaceae Rostovzev

Genus

Cololejeunea (Spruce) Schiffn.

Species

Cololejeunea setiloba A. Evans

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