Big Bluet vs Coastal Ragweed

Enallagma durum compared with Ambrosia hispida

Taxonomic Classification

Rank	Big Bluet	Coastal Ragweed
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Magnoliophyta (Flowering Plants)
Class	Insecta (Insects)	Magnoliopsida (Dicots)
Order	Odonata (Odonata)	Asterales (Daisies & Sunflowers)
Family	Coenagrionidae	Asteraceae (Daisy Family)
Genus	Enallagma	Ambrosia
Species	Enallagma durum	Ambrosia hispida

Conservation Status

Big Bluet

LC — Least Concern

Coastal Ragweed

LC — Least Concern

Physical Characteristics

Attribute	Big Bluet	Coastal Ragweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Big Bluet

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Found in United States.

Coastal Ragweed

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Found in Cuba.

Big Bluet

The Big Bluet (Enallagma durum) is a species in the genus Enallagma. It is currently classified as Least Concern on the IUCN Red List. Typically found in virtually all terrestrial and freshwater habitats.

Coastal Ragweed

Coastal ragweed (Ambrosia hispida) is a perennial herb in the family Asteraceae, native to the coastal dunes, sandy beaches, and cays of Cuba, the Bahamas, and the wider Caribbean region. It grows in pioneer beach and dune vegetation, often forming spreading colonies that help stabilise loose coastal sands. Like other members of the genus Ambrosia, it bears inconspicuous greenish-white flowers arranged in racemes; male flower heads produce wind-dispersed pollen that can trigger allergic rhinitis in sensitive individuals. The deeply lobed, hispid leaves are adapted to reflect intense solar radiation and tolerate salt spray. Coastal ragweed plays an ecological role in early dune succession, binding sand and enabling other plant species to establish. The genus is widespread globally, with several Ambrosia species considered noxious weeds in agricultural settings, though Ambrosia hispida is restricted to its native Caribbean coastal range. The IUCN assesses it as Least Concern, reflecting adequate population size across its Caribbean coastal distribution. Pressure from coastal development and tourism infrastructure poses a localised threat to dune communities it inhabits.