North America Native Plant

Jagleaf Junglefern

Botanical name: Megalastrum subincisa

USDA symbol: MESU3

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico  

Synonyms: Ctenitis subincisa (Willd.) Ching (CTSU)  âš˜  Dryopteris subincisa (Willd.) Urb. (DRSU6)   

Jagleaf Junglefern: A Tropical Native Worth Knowing If you’ve ever wandered through Puerto Rico’s lush mountain forests and spotted an elegant fern with deeply serrated fronds that look like they were carved by nature’s most artistic hand, you’ve likely encountered the jagleaf junglefern (Megalastrum subincisa). This native Puerto Rican beauty ...

Jagleaf Junglefern: A Tropical Native Worth Knowing

If you’ve ever wandered through Puerto Rico’s lush mountain forests and spotted an elegant fern with deeply serrated fronds that look like they were carved by nature’s most artistic hand, you’ve likely encountered the jagleaf junglefern (Megalastrum subincisa). This native Puerto Rican beauty is a testament to the island’s incredible botanical diversity, though it remains relatively unknown outside its homeland.

What Makes This Fern Special?

The jagleaf junglefern is a perennial fern that’s perfectly adapted to Puerto Rico’s tropical climate. Unlike the more common ferns you might know, this species sports distinctively jagged-edged fronds that give it both its common name and its striking appearance. As a member of the Megalastrum genus, it’s related to other tropical shield ferns but has its own unique character.

Botanically speaking, you might also see this plant referenced under its older scientific names, including Ctenitis subincisa or Dryopteris subincisa, as plant classifications have evolved over time.

Where Does It Call Home?

This fern is exclusively native to Puerto Rico, where it thrives in the island’s mountainous regions. It’s what botanists call an endemic species – meaning it naturally occurs nowhere else on Earth. In Puerto Rico, you’ll find it flourishing in the understory of humid forests, where it enjoys the dappled light and consistent moisture that filter down through the canopy.

Garden Potential and Landscape Role

For gardeners in tropical zones (USDA zones 10-11), the jagleaf junglefern can be a stunning addition to shade gardens and tropical landscapes. Here’s why you might want to consider it:

  • Adds dramatic texture with its deeply serrated fronds
  • Provides year-round greenery as a perennial
  • Perfect for understory plantings beneath trees
  • Creates an authentic tropical forest feel
  • Excellent for woodland gardens and naturalized areas

Growing Conditions and Care

If you’re lucky enough to garden in a suitable climate, here’s what this fern needs to thrive:

Light: Partial to full shade – think forest understory conditions. Direct sunlight will stress or damage the fronds.

Moisture: This fern has a facultative wetland status, meaning it usually grows in moist conditions but can tolerate some variation. Keep soil consistently moist but well-draining.

Soil: Rich, organic soil that mimics forest floor conditions works best. Good drainage is essential to prevent root rot.

Humidity: High humidity is crucial – this is a tropical plant that expects tropical conditions.

Is It Right for Your Garden?

The jagleaf junglefern is definitely a specialist plant. Unless you’re gardening in a tropical climate with the ability to provide consistent shade, moisture, and humidity, this isn’t the fern for you. However, if you’re in zones 10-11 and looking to create an authentic tropical garden or naturalized woodland area, it could be a fantastic choice.

Keep in mind that as a Puerto Rico endemic, finding this plant may be challenging outside its native range. If you do locate it, make sure you’re purchasing from reputable sources that practice sustainable collection methods.

The Bottom Line

The jagleaf junglefern represents the unique botanical heritage of Puerto Rico. While it may not be suitable for most gardeners due to its specific climate requirements, those in appropriate zones will find it to be a distinctive and beautiful addition to their shade gardens. Its jagged fronds and forest-floor presence make it a conversation piece that connects your garden to the wild beauty of Caribbean mountain forests.

For most gardeners in temperate climates, local native ferns will be better choices, but for tropical gardeners seeking something special and regionally appropriate, Megalastrum subincisa offers a chance to grow a truly unique piece of Puerto Rican nature.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Caribbean

FACW

Facultative Wetland - Plants with this status usually occurs in wetlands but may occur in non-wetlands

Jagleaf Junglefern

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

Megalastrum Holttum - megalastrum

Species

Megalastrum subincisa (Willd.) A.R. Sm. & R.C. Moran - jagleaf junglefern

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