North America Native Plant

Mona Island Sandmat

Botanical name: Chamaesyce orbifolia

USDA symbol: CHOR6

Life cycle: perennial

Habit: subshrub

Native status: Native to Puerto Rico  

Mona Island Sandmat: A Rare Caribbean Native Worth Knowing Meet the Mona Island sandmat (Chamaesyce orbifolia), a little-known perennial herb that calls Puerto Rico home. While you probably won’t find this plant at your local nursery, it’s worth understanding this unique member of the spurge family and what makes it ...

Mona Island Sandmat: A Rare Caribbean Native Worth Knowing

Meet the Mona Island sandmat (Chamaesyce orbifolia), a little-known perennial herb that calls Puerto Rico home. While you probably won’t find this plant at your local nursery, it’s worth understanding this unique member of the spurge family and what makes it special in the world of native Caribbean flora.

What Is Mona Island Sandmat?

Chamaesyce orbifolia is a perennial forb—essentially a non-woody plant that comes back year after year. As its common name suggests, this plant has strong ties to Mona Island, a small island between Puerto Rico and the Dominican Republic. Like other plants in the Chamaesyce genus, it’s part of the spurge family and likely produces the characteristic milky sap that these plants are known for.

Where Does It Grow?

This plant is native exclusively to Puerto Rico, making it what botanists call an endemic species. Its distribution appears to be quite limited, which isn’t uncommon for island plants that evolved in isolation.

Should You Plant Mona Island Sandmat?

Here’s where things get tricky. While we’d love to give you the full scoop on growing this native beauty, Chamaesyce orbifolia falls into that category of plants that are more important for conservation than cultivation. Its limited range and lack of availability in the horticultural trade suggest this might be a rare species that’s best left to specialized conservation efforts.

What We Know About Its Growth

As a perennial forb, Mona Island sandmat lacks woody stems and likely stays relatively low to the ground—a common trait among sandmat species. The orbifolia part of its name hints at round or circular leaves, though specific details about its appearance are limited in available literature.

Conservation Considerations

If you’re a gardener in Puerto Rico interested in native plants, it’s worth noting that endemic species like Chamaesyce orbifolia play crucial roles in local ecosystems. However, due to the apparent rarity of this plant, we’d recommend focusing on other well-documented Puerto Rican natives for your garden.

Alternative Native Options

Instead of seeking out this rare sandmat, consider these more readily available Puerto Rican natives:

  • Other Chamaesyce species that may be more common
  • Native coastal plants adapted to sandy soils
  • Well-established endemic species available through local native plant societies

The Bottom Line

Mona Island sandmat represents the fascinating but fragile world of Caribbean island endemics. While it’s not a plant most gardeners will grow, understanding species like this helps us appreciate the incredible diversity of native plants and the importance of protecting their natural habitats. If you’re passionate about rare natives, consider supporting conservation organizations working to protect Puerto Rico’s unique flora instead of trying to cultivate this elusive species.

Sometimes the best way to honor a native plant is to let it thrive where nature intended—especially when that place is as special and fragile as the ecosystems of Mona Island.

Mona Island Sandmat

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

Euphorbiales

Family

Euphorbiaceae Juss. - Spurge family

Genus

Chamaesyce Gray - sandmat

Species

Chamaesyce orbifolia Alain - Mona Island sandmat

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