North America Native Plant

Las Cuevas Mountainbay

Botanical name: Calyptranthes estremenae

USDA symbol: CAES

Life cycle: perennial

Habit: tree

Native status: Native to Puerto Rico  

Las Cuevas Mountainbay: A Critically Endangered Puerto Rican Treasure Meet the Las Cuevas mountainbay (Calyptranthes estremenae), one of Puerto Rico’s most precious and precarious native plants. This isn’t your typical how to grow it in your backyard plant profile – instead, it’s a story about conservation, rarity, and why some ...

Rare plant alert!

Region: Conservation status by state

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) ⚘

Las Cuevas Mountainbay: A Critically Endangered Puerto Rican Treasure

Meet the Las Cuevas mountainbay (Calyptranthes estremenae), one of Puerto Rico’s most precious and precarious native plants. This isn’t your typical how to grow it in your backyard plant profile – instead, it’s a story about conservation, rarity, and why some plants are better admired from afar.

What Makes This Plant Special?

Las Cuevas mountainbay is a perennial tree native exclusively to Puerto Rico. As its common name suggests, this species has strong ties to the Las Cuevas area, making it what botanists call an endemic species – meaning it exists nowhere else on Earth naturally.

This tree typically grows as a single-trunked specimen reaching heights greater than 13-16 feet, though environmental conditions can sometimes result in shorter, multi-stemmed growth forms.

Geographic Distribution and Native Status

Calyptranthes estremenae grows only in Puerto Rico, where it clings to existence in what are likely montane forest environments. Its entire world range is confined to this single Caribbean island, making every individual plant incredibly valuable from a biodiversity perspective.

A Conservation Crisis

Here’s where this plant’s story takes a serious turn. Las Cuevas mountainbay has a Global Conservation Status of S1, which translates to Critically Imperiled. This designation means the species faces an extremely high risk of extinction due to extreme rarity, with typically five or fewer known occurrences and very few remaining individuals (fewer than 1,000 plants total).

This isn’t just uncommon – this is hanging-by-a-thread rare.

Should You Plant Las Cuevas Mountainbay?

The short answer is: probably not, and here’s why. With so few individuals remaining in the wild, every plant matters enormously for the species’ survival. Unless you’re working with conservation organizations and have access to responsibly sourced material through legitimate conservation programs, this tree should remain off your planting list.

Growing Conditions and Care

While specific growing requirements for Las Cuevas mountainbay aren’t well-documented (partly due to its rarity), we can make educated guesses based on its Puerto Rican origins:

  • USDA Hardiness Zones: Likely 10-11 (tropical climate)
  • Habitat: Probably montane forest conditions
  • Climate: Warm, humid tropical environment
  • Soil: Likely well-draining forest soils

What Can You Do Instead?

If you’re passionate about Puerto Rican native plants, consider these alternatives:

  • Support conservation organizations working to protect rare Puerto Rican species
  • Plant other native Puerto Rican trees that are more common and available through legitimate nurseries
  • Create habitat for native wildlife that might benefit rare species like Las Cuevas mountainbay
  • Spread awareness about the importance of plant conservation

The Bigger Picture

Las Cuevas mountainbay represents something bigger than just one rare tree. It’s a reminder that our planet’s plant diversity includes countless species that exist in tiny populations, often in very specific locations. These plants are irreplaceable libraries of genetic information and ecological relationships that have taken millions of years to develop.

While you might not be able to grow this particular mountainbay in your garden, you can still play a role in plant conservation by choosing native plants appropriate for your region, supporting conservation efforts, and spreading the word about the importance of protecting rare species like this remarkable Puerto Rican endemic.

Sometimes the most responsible way to appreciate a plant is to leave it where it belongs – clinging to existence in its native habitat, where every individual counts toward the species’ survival.

Las Cuevas Mountainbay

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Myrtales

Family

Myrtaceae Juss. - Myrtle family

Genus

Calyptranthes Sw. - mountainbay

Species

Calyptranthes estremenae Alain - Las Cuevas mountainbay

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