North America Native Plant

Scaly Dwarf Polypody

Botanical name: Grammitis cultrata

USDA symbol: GRCU

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico  

Synonyms: Polypodium cultratum Willd. (POCU11)   

Scaly Dwarf Polypody: A Rare Puerto Rican Fern Worth Knowing If you’re a fern enthusiast or someone fascinated by rare tropical plants, you might have stumbled across the name Grammitis cultrata, commonly known as the scaly dwarf polypody. This little-known fern species is a true Puerto Rican native that deserves ...

Scaly Dwarf Polypody: A Rare Puerto Rican Fern Worth Knowing

If you’re a fern enthusiast or someone fascinated by rare tropical plants, you might have stumbled across the name Grammitis cultrata, commonly known as the scaly dwarf polypody. This little-known fern species is a true Puerto Rican native that deserves a spot in our botanical awareness, even if it’s not destined for your average backyard garden.

What Exactly is Scaly Dwarf Polypody?

The scaly dwarf polypody (Grammitis cultrata) is a perennial fern native exclusively to Puerto Rico. You might also see it listed under its botanical synonym, Polypodium cultratum Willd., in older botanical references. As its common name suggests, this is a small fern species characterized by its scaly appearance – a feature that helps distinguish it from other tropical ferns in its native habitat.

Like all ferns, Grammitis cultrata reproduces through spores rather than seeds and doesn’t produce the showy flowers that attract pollinators. Instead, it plays a different ecological role in its native Puerto Rican ecosystems.

Where Does It Call Home?

This fern is endemic to Puerto Rico, meaning it naturally occurs nowhere else in the world. Its limited geographic distribution makes it a special piece of Puerto Rico’s unique botanical heritage.

Is It Beneficial to Have in a Garden?

While the scaly dwarf polypody might not be the showstopper that flowering native plants can be, ferns like this one do offer several garden benefits:

  • They add texture and year-round green color to shaded areas
  • Ferns help create naturalistic, forest-like atmospheres in tropical gardens
  • They can contribute to local ecosystem health by providing habitat structure
  • As native plants, they support the biodiversity of their region

However, it’s worth noting that very little specific information is available about this particular fern’s cultivation requirements, wildlife interactions, or availability in the nursery trade. This suggests it might be quite rare or challenging to grow outside its natural habitat.

How to Identify Scaly Dwarf Polypody

Identifying Grammitis cultrata can be tricky without detailed botanical knowledge, but here are the key characteristics to look for:

  • Size: As the name dwarf suggests, this is a small fern species
  • Scales: Look for the distinctive scaly appearance that gives it its common name
  • Location: In the wild, you’d only find it in Puerto Rico
  • Growth pattern: It grows as a perennial, returning year after year

A Word of Caution for Gardeners

If you’re a gardener in Puerto Rico interested in native ferns, the scaly dwarf polypody presents an interesting dilemma. While supporting native plants is always admirable, the limited information available about this species suggests it might be rare or sensitive. If you do encounter it or have the opportunity to grow it, make sure any plant material is responsibly sourced and legally obtained.

For most gardeners outside of Puerto Rico, this fern would be completely unsuitable due to climate requirements. Instead, consider researching native ferns in your own region – every area has its own fascinating fern species that would be better adapted to local conditions.

The Bottom Line

The scaly dwarf polypody represents one of those fascinating botanical puzzle pieces that make up Puerto Rico’s unique flora. While it might not be the next big thing in garden centers, understanding and appreciating these specialized native species helps us better value the incredible diversity of plant life on our planet. Sometimes the most interesting plants are the ones we can’t easily grow – they remind us that nature’s complexity extends far beyond our garden gates.

Scaly Dwarf Polypody

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Grammitidaceae Newman - Kihi Fern family

Genus

Grammitis Sw. - dwarf polypody

Species

Grammitis cultrata (Willd.) Proctor - scaly dwarf polypody

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