North America Native Plant

Small-leaf Squarestem

Botanical name: Melanthera parvifolia

USDA symbol: MEPA3

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Melanthera radiata Small (MERA3)   

Small-Leaf Squarestem: A Rare Native Florida Wildflower Worth Protecting If you’re passionate about native Florida gardening and have a soft spot for rare botanical treasures, meet the small-leaf squarestem (Melanthera parvifolia). This unassuming perennial forb might not be the showiest plant in your garden, but it carries the special distinction ...

Rare plant alert!

Region: Conservation status by state

Status: S2Q: Status is uncertain but is somewhere between the following rankings: Uncertain taxonomy: ⚘ Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘

Small-Leaf Squarestem: A Rare Native Florida Wildflower Worth Protecting

If you’re passionate about native Florida gardening and have a soft spot for rare botanical treasures, meet the small-leaf squarestem (Melanthera parvifolia). This unassuming perennial forb might not be the showiest plant in your garden, but it carries the special distinction of being a true Florida endemic – and one that needs our help to thrive.

What Makes Small-Leaf Squarestem Special?

Small-leaf squarestem belongs to the sunflower family (Asteraceae) and lives up to its name with distinctively small leaves and square stems. As a perennial forb, it lacks the woody tissue of shrubs and trees, instead putting its energy into producing cheerful yellow composite flowers that are characteristic of its plant family.

This native gem is found exclusively in Florida, making it a true state treasure. However, its rarity is both what makes it special and what makes it concerning – small-leaf squarestem has a Global Conservation Status of S2Q, indicating it’s rare and its status needs further study.

Where Does It Grow?

Small-leaf squarestem is endemic to Florida, meaning it grows nowhere else in the world naturally. This makes Florida gardeners the exclusive stewards of this species in cultivation.

Should You Plant Small-Leaf Squarestem?

Here’s where things get both exciting and important: if you’re a Florida native plant enthusiast, small-leaf squarestem could be a meaningful addition to your garden – but only if you source it responsibly. Because of its rarity status, it’s crucial that any plants you acquire come from ethical suppliers who propagate from existing cultivated stock rather than wild-collecting.

This plant is perfect for:

  • Native Florida plant collections
  • Conservation-minded gardeners
  • Naturalized garden areas
  • Pollinator-supporting landscapes

Growing Conditions and Care

While specific growing information for small-leaf squarestem is limited due to its rarity, we can make educated assumptions based on its Florida native status and plant family characteristics:

  • Hardiness: Likely thrives in USDA zones 9-11
  • Light: Probably prefers full to partial sun
  • Soil: Likely adapted to sandy Florida soils with good drainage
  • Water: Once established, should be relatively drought-tolerant like many Florida natives

Pollinator and Wildlife Benefits

As a member of the sunflower family, small-leaf squarestem likely provides nectar for butterflies, bees, and other pollinators. Its flowers may also produce seeds that could feed small birds, though specific wildlife relationships haven’t been well-documented for this rare species.

A Note on Responsible Gardening

If you decide to grow small-leaf squarestem, you’re becoming part of an important conservation effort. By cultivating rare native species in our gardens, we create backup populations and help ensure these plants don’t disappear entirely. Just remember: always source your plants from reputable native plant nurseries that propagate rather than wild-collect, and consider sharing seeds or divisions with other conservation-minded gardeners.

Small-leaf squarestem may not be the easiest native plant to find or the most dramatic in your garden, but for the right gardener, it offers the special satisfaction of growing something truly unique to Florida – and helping preserve it for future generations.

Small-leaf Squarestem

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Melanthera Rohr - squarestem

Species

Melanthera parvifolia Small - small-leaf squarestem

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