North America Native Plant

Robust Clubmoss

Botanical name: Lycopodiella ×robusta

USDA symbol: LYRO

Life cycle: perennial

Habit: nonvascular

Native status: Native to the lower 48 states  

Synonyms: Lycopodium inundatum L. var. robustum R.J. Eaton (LYINR)   

Robust Clubmoss: A Rare Native Treasure You’ll Probably Never See (And Shouldn’t Try to Grow) Meet robust clubmoss (Lycopodiella ×robusta), one of nature’s most elusive little green mysteries. This isn’t your typical garden plant – in fact, it’s not a garden plant at all! This rare hybrid clubmoss is more ...

Rare plant alert!

Region: Conservation status by state

Status: S1S3: 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) ⚘ 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 ⚘

Robust Clubmoss: A Rare Native Treasure You’ll Probably Never See (And Shouldn’t Try to Grow)

Meet robust clubmoss (Lycopodiella ×robusta), one of nature’s most elusive little green mysteries. This isn’t your typical garden plant – in fact, it’s not a garden plant at all! This rare hybrid clubmoss is more like finding a botanical unicorn in the wild, and here’s why you should know about it even if you’ll likely never encounter it in person.

What Exactly Is Robust Clubmoss?

Despite its name, robust clubmoss isn’t actually a moss at all. It’s a lycopod, which puts it in the same ancient family tree as ferns – these plants have been around since before dinosaurs walked the earth! Lycopodiella ×robusta is what botanists call a hybrid, meaning it’s the offspring of two different clubmoss species that decided to get together and create something new.

This perennial plant has a terrestrial growth habit, meaning it grows on land rather than in water. Like other bryophytes, it’s herbaceous and often attaches itself to solid surfaces like rocks or decaying wood rather than growing directly in soil.

Where Does It Call Home?

Robust clubmoss is native to the lower 48 states, but don’t go packing your bags to find it just yet. This little guy has a very limited range, currently known only from Maine and Massachusetts. Its distribution is so narrow that you’re more likely to spot Bigfoot than stumble across this rare clubmoss!

The Rarity Factor: Handle With Care

Here’s where things get serious: robust clubmoss has a Global Conservation Status of S1S3, which indicates it’s quite rare and potentially vulnerable. This means that even if you somehow managed to find it in the wild, you should absolutely leave it alone. These plants are rare for a reason, and disturbing their natural habitat could harm already fragile populations.

Is It Good for Your Garden?

The short answer? No, and here’s why:

  • It’s far too rare to be collected or cultivated responsibly
  • It has extremely specialized growing requirements that are nearly impossible to replicate in a garden setting
  • As a hybrid species, it may have unpredictable characteristics
  • It reproduces via spores rather than seeds, making propagation extremely challenging

Unlike flowering plants that attract pollinators, clubmosses don’t produce flowers or offer nectar. They’re fascinating from a botanical perspective, but they don’t provide the typical wildlife benefits that most gardeners are looking for.

How to Identify Robust Clubmoss (If You’re Lucky Enough to See One)

Since specific identification details for this hybrid are limited, you’d need to rely on general clubmoss characteristics:

  • Small, scale-like leaves arranged along creeping stems
  • Low-growing, carpet-like appearance
  • Found in specialized habitats in Maine and Massachusetts
  • May be found attached to rocks or decaying wood

If you think you’ve spotted one, take photos but don’t disturb it – and consider contacting local botanists or conservation groups who would be thrilled to know about it!

The Bottom Line

Robust clubmoss is one of those plants that’s incredibly important for biodiversity and scientific understanding, but it’s not destined for your backyard garden bed. Its rarity makes it a conservation priority rather than a cultivation target. Instead, if you’re interested in supporting native plants in your landscape, focus on more common (and garden-appropriate) native species that can actually thrive in cultivation while supporting local wildlife.

Sometimes the best way to appreciate a plant is simply knowing it exists and doing our part to protect the wild spaces where it can continue to thrive undisturbed.

Robust Clubmoss

Classification

Group

Lycopod

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Lycopodiophyta - Lycopods

Subdivision
Class

Lycopodiopsida

Subclass
Order

Lycopodiales

Family

Lycopodiaceae P. Beauv. ex Mirb. - Club-moss family

Genus

Lycopodiella Holub - clubmoss

Species

Lycopodiella ×robusta (R.J. Eaton) A. Haines [alopecuroides × inundata] - robust clubmoss

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