North America Native Plant

Puerto Rico Maidenhair

Botanical name: Adiantum vivesii

USDA symbol: ADVI4

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico  

Puerto Rico Maidenhair: A Critically Endangered Fern Worth Protecting Meet the Puerto Rico maidenhair (Adiantum vivesii), one of the Caribbean’s most endangered ferns and a true botanical treasure that’s teetering on the edge of extinction. This delicate species represents everything we love about native plants—and everything we stand to lose ...

Rare plant alert!

Region: United States

Status: S1: 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) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Status: Endangered: 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) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Puerto Rico Maidenhair: A Critically Endangered Fern Worth Protecting

Meet the Puerto Rico maidenhair (Adiantum vivesii), one of the Caribbean’s most endangered ferns and a true botanical treasure that’s teetering on the edge of extinction. This delicate species represents everything we love about native plants—and everything we stand to lose if we don’t act as responsible stewards of our natural heritage.

What Makes This Fern Special?

The Puerto Rico maidenhair belongs to the beloved maidenhair fern family, known for their impossibly delicate, fan-shaped fronds that seem to dance at the slightest breeze. As a perennial forb (a non-woody vascular plant), this species embodies the graceful beauty that makes maidenhair ferns garden favorites worldwide. However, Adiantum vivesii is far from your typical garden center find.

A Rare Caribbean Endemic

This extraordinary fern is found nowhere else on Earth except Puerto Rico, making it what botanists call an endemic species. Currently, Adiantum vivesii holds the sobering conservation status of S1, meaning it’s critically imperiled with typically five or fewer known occurrences and fewer than 1,000 remaining individuals in the wild. It’s also listed as Endangered, putting it in the same category as some of the world’s most threatened wildlife.

Why You Shouldn’t Plant This Fern (And What You Can Do Instead)

Here’s where we need to have an important conversation about conservation ethics. While the Puerto Rico maidenhair would undoubtedly be a stunning addition to any shade garden, its critically endangered status means it should remain off-limits to home gardeners. Here’s why:

  • With so few plants remaining in the wild, any collection could push the species closer to extinction
  • This fern likely requires very specific growing conditions that are difficult to replicate outside its native habitat
  • Every remaining plant is crucial for the species’ survival and potential recovery

Supporting Conservation Instead

Rather than trying to grow this rare beauty, consider these meaningful alternatives:

  • Plant other maidenhair fern species that are readily available and sustainably propagated
  • Support organizations working on Puerto Rican plant conservation
  • Choose other native plants from your region to support local ecosystems
  • Spread awareness about endangered plant species and their importance

Identifying Puerto Rico Maidenhair

If you’re ever fortunate enough to visit Puerto Rico and encounter native ferns, the Puerto Rico maidenhair would display the characteristic features of its genus: delicate, fan-shaped leaflets on thin, dark stems. However, given its extreme rarity, any potential sighting should be reported to local botanists or conservation organizations rather than disturbed.

The Bigger Picture

The Puerto Rico maidenhair serves as a powerful reminder of why native plant gardening matters. While we can’t grow this particular species, we can honor its existence by making thoughtful choices about the plants we do grow. By selecting native species appropriate to our own regions, we’re supporting biodiversity, creating habitat for local wildlife, and reducing the pressure on wild plant populations.

Sometimes the most beautiful act of gardening is knowing when not to dig, when not to collect, and when to let nature’s rarest treasures remain exactly where they belong—in the wild, fighting for another day, another generation, another chance at survival.

Puerto Rico Maidenhair

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Pteridaceae E.D.M. Kirchn. - Maidenhair Fern family

Genus

Adiantum L. - maidenhair fern

Species

Adiantum vivesii Proctor - Puerto Rico maidenhair

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