North America Native Plant

Gymnomitrion Mucrophorum

Botanical name: Gymnomitrion mucrophorum

USDA symbol: GYMU4

Habit: nonvascular

Native status: Native to North America  

Gymnomitrion mucrophorum: A Critically Rare North American Liverwort Meet one of North America’s most elusive botanical treasures: Gymnomitrion mucrophorum. If you’ve never heard of this tiny plant, you’re definitely not alone. This microscopic marvel belongs to the fascinating world of liverworts, and it’s so rare that you’re more likely to ...

Rare plant alert!

Region: Conservation status by state

Status: S1: 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) ⚘

Gymnomitrion mucrophorum: A Critically Rare North American Liverwort

Meet one of North America’s most elusive botanical treasures: Gymnomitrion mucrophorum. If you’ve never heard of this tiny plant, you’re definitely not alone. This microscopic marvel belongs to the fascinating world of liverworts, and it’s so rare that you’re more likely to spot a unicorn in your backyard than encounter this little green gem in the wild.

What Exactly Is a Liverwort?

Before we dive into the specifics of our star plant, let’s talk about what liverworts are. Think of them as the quiet cousins of mosses – they’re small, green, and love hanging out in damp places. Liverworts are some of the oldest land plants on Earth, having been around for about 400 million years. They’re tough little survivors that don’t need fancy root systems or flashy flowers to make their mark on the world.

Gymnomitrion mucrophorum is what we call a terrestrial liverwort, meaning it prefers to set up shop on solid surfaces like rocks, dead wood, or sometimes the bark of living trees rather than growing directly in soil. It’s completely herbaceous (no woody parts here!) and has that characteristic leafy appearance that makes liverworts look like tiny, flattened ferns.

A North American Native with a Big Problem

This little liverwort is a true North American native, but here’s where things get serious. Gymnomitrion mucrophorum has a Global Conservation Status of S1, which translates to Critically Imperiled. In plain English, this means it’s hanging on by a thread with typically five or fewer known locations and fewer than 1,000 individual plants in existence.

The exact geographical distribution of this species remains somewhat mysterious, partly because it’s so incredibly rare and partly because liverworts are notoriously difficult to study and identify in the field.

Why This Matters for Your Garden (And Why You Shouldn’t Try to Grow It)

Now, you might be thinking, If it’s so rare, shouldn’t I try to grow it to help save the species? While that instinct comes from a good place, the answer is a firm no. Here’s why:

  • Its extreme rarity means every individual plant in the wild is precious
  • We don’t fully understand its specific growing requirements
  • Disturbing wild populations could push it closer to extinction
  • It likely requires very specific microhabitat conditions that are nearly impossible to replicate

How to Identify Gymnomitrion mucrophorum (Just in Case)

While the chances of stumbling across this liverwort are astronomically small, here’s what to look for if you’re exploring rocky areas or old-growth forests:

  • Tiny, leafy green plants growing on rock surfaces or dead wood
  • Flattened, scale-like leaves arranged in a distinctive pattern
  • No flowers or seeds (liverworts reproduce via spores)
  • Usually found in small patches or individual plants

If you think you’ve found something that might be Gymnomitrion mucrophorum, don’t touch it! Instead, take photos and contact your local botanical survey or university extension office. You could be looking at one of North America’s rarest plants.

Supporting Liverwort Conservation

While you can’t grow this particular species, you can still support liverwort conservation in your garden and beyond:

  • Create liverwort-friendly conditions by maintaining damp, shaded areas with rocks or logs
  • Avoid using chemicals that might harm these sensitive plants
  • Support organizations working on bryophyte (moss and liverwort) conservation
  • Learn about and appreciate the common liverworts that might already be living in your garden

The Bigger Picture

Gymnomitrion mucrophorum reminds us that not every native plant is suitable for cultivation, and that’s okay. Sometimes the best way to appreciate a plant is from afar, knowing that it exists in its wild home, however precariously. These tiny liverworts play important roles in their ecosystems, even if we don’t fully understand all of them yet.

Rather than trying to grow this critically rare species, consider exploring the wonderful world of more common liverworts and mosses that can add texture and ancient beauty to shaded corners of your garden. You’ll be supporting biodiversity while leaving the ultra-rare species to the conservation experts.

After all, some of nature’s most precious treasures are meant to be admired, not collected.

Gymnomitrion Mucrophorum

Classification

Group

Liverwort

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Hepaticophyta - Liverworts

Subdivision

Hepaticae

Class

Hepaticopsida

Subclass

Jungermanniae

Order

Jungermanniales

Family

Gymnomitriaceae H. Klinggr.

Genus

Gymnomitrion Corda, nom. cons.

Species

Gymnomitrion mucrophorum R.M. Schust.

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