North America Native Plant

Blackspore Oakfern

Botanical name: Gymnocarpium ×heterosporum

USDA symbol: GYHE3

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Gymnocarpium heterosporum W.H. Wagner, database artifact (GYHE)   

Blackspore Oakfern: A Rare Hybrid Fern Worth Knowing About Meet the blackspore oakfern (Gymnocarpium ×heterosporum), one of nature’s more mysterious botanical creations. This isn’t your typical garden center find – it’s a hybrid fern that’s about as rare as a unicorn in the plant world, and just as fascinating once ...

Blackspore Oakfern: A Rare Hybrid Fern Worth Knowing About

Meet the blackspore oakfern (Gymnocarpium ×heterosporum), one of nature’s more mysterious botanical creations. This isn’t your typical garden center find – it’s a hybrid fern that’s about as rare as a unicorn in the plant world, and just as fascinating once you know its story.

What Makes This Fern Special?

The × in its scientific name gives away the secret – this is a hybrid fern, meaning it’s the result of two different oakfern species getting together to create something entirely new. Blackspore oakfern is a perennial that produces delicate, triangular fronds characteristic of the oakfern family, but with its own unique twist in the spore department (hence the blackspore common name).

Where Can You Find It?

Here’s where things get really interesting – and rare. This native fern has been documented only in Pennsylvania, making it one of the most geographically restricted ferns in North America. Its extremely limited distribution means you’re unlikely to stumble across it on a casual woodland walk.

Should You Grow Blackspore Oakfern?

This is where we need to pump the brakes a bit. Given its rarity and extremely limited natural range, blackspore oakfern falls into the look but don’t touch category for most gardeners. If you’re absolutely determined to grow this botanical rarity, you’ll need to ensure any plant material is responsibly sourced and ethically obtained.

Garden Role and Design Potential

In the unlikely event you do acquire this fern legitimately, it would serve as:

  • A conversation-starting specimen plant
  • Groundcover in deeply shaded woodland gardens
  • Part of a specialized native fern collection
  • A living piece of botanical history

Growing Conditions

While specific cultivation information for this hybrid is scarce, we can make educated guesses based on its oakfern parentage:

  • Light: Deep to partial shade
  • Soil: Moist, well-draining, rich in organic matter
  • Moisture: Consistent moisture without waterlogging
  • Hardiness: Likely zones 4-8, though this is speculative

Wildlife and Pollinator Benefits

Like all ferns, blackspore oakfern doesn’t produce flowers, so it won’t attract pollinators. However, it can provide habitat for small woodland creatures and adds to the overall biodiversity of a woodland ecosystem.

Better Alternatives for Your Garden

Instead of hunting for this rare hybrid, consider these more readily available native oakferns that offer similar woodland charm:

  • Common oakfern (Gymnocarpium dryopteris)
  • Limestone oakfern (Gymnocarpium robertianum)
  • Other native woodland ferns like Christmas fern or lady fern

The Bottom Line

Blackspore oakfern is undeniably cool from a botanical perspective – a rare hybrid that represents nature’s experimental side. But for most gardeners, admiring it from afar (or in botanical literature) is the most responsible approach. Focus your woodland garden efforts on more common native ferns that can provide similar aesthetic appeal without the ethical complications of growing extremely rare plants.

Sometimes the best way to appreciate nature’s rarities is to let them stay rare and wild where they belong.

Blackspore Oakfern

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Dryopteridaceae Herter - Wood Fern family

Genus

Gymnocarpium Newman - oakfern

Species

Gymnocarpium ×heterosporum W.H. Wagner (pro sp.) [appalachianum × robertianum] - blackspore oakfern

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