North America Native Plant

Sherring’s Dwarf Polypody

Botanical name: Grammitis sherringii

USDA symbol: GRSH

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico  

Sherring’s Dwarf Polypody: A Rare Puerto Rican Fern Worth Knowing About Meet Sherring’s dwarf polypody (Grammitis sherringii), one of Puerto Rico’s lesser-known botanical treasures. This diminutive fern might not be gracing garden centers anytime soon, but it’s worth understanding what makes this tiny tropical native so special. What Exactly Is ...

Sherring’s Dwarf Polypody: A Rare Puerto Rican Fern Worth Knowing About

Meet Sherring’s dwarf polypody (Grammitis sherringii), one of Puerto Rico’s lesser-known botanical treasures. This diminutive fern might not be gracing garden centers anytime soon, but it’s worth understanding what makes this tiny tropical native so special.

What Exactly Is Sherring’s Dwarf Polypody?

Despite some confusion in botanical databases that occasionally list it as a forb, Sherring’s dwarf polypody is actually a true fern belonging to the Grammitidaceae family. As its common name suggests, this is a small-statured fern that likely grows as an epiphyte or on rocky surfaces in its native habitat.

This perennial fern represents one of many endemic species that make Puerto Rico’s flora so unique and biodiverse.

Where Does It Call Home?

Sherring’s dwarf polypody is native exclusively to Puerto Rico, where it likely inhabits the island’s cloud forests and other humid, mountainous regions. This limited geographic distribution makes it a true island endemic.

The Challenge of Growing Sherring’s Dwarf Polypody

Here’s the reality check: if you’re dreaming of adding this fern to your garden, you’re probably out of luck. Grammitis sherringii appears to be extremely rare and isn’t available through typical horticultural channels. In fact, so little is documented about this species that basic cultivation requirements remain largely unknown.

Why This Matters for Native Plant Enthusiasts

While you likely can’t grow Sherring’s dwarf polypody in your garden, understanding rare species like this one helps us appreciate:

  • The incredible biodiversity found in small island ecosystems
  • The importance of habitat conservation
  • Why protecting native plant communities matters
  • The gaps that still exist in our botanical knowledge

What We Can Learn About Growing Conditions

Based on Puerto Rico’s climate and the habitat preferences of related Grammitis species, this fern would likely prefer:

  • High humidity levels
  • Filtered or dappled light
  • Well-draining but consistently moist growing medium
  • Warm temperatures year-round
  • Good air circulation

Alternative Native Ferns to Consider

If you’re inspired by Puerto Rico’s native ferns but need something actually obtainable, consider researching other Caribbean native ferns that might be available through specialty native plant nurseries. Always ensure any plants you purchase are ethically and legally sourced.

The Conservation Connection

Species like Sherring’s dwarf polypody remind us why supporting native plant conservation efforts matters. Whether through habitat protection, botanical research funding, or simply spreading awareness about rare native species, we all play a role in preserving these botanical treasures for future generations.

While you may never see this particular fern in person, knowing it exists somewhere in Puerto Rico’s misty mountains adds a little magic to our understanding of the plant world’s incredible diversity.

Sherring’s 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 sherringii (Baker) Proctor - Sherring's 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