Coastal Ragweed vs Rootless Duckweed

Ambrosia hispida compared with Wolffia arrhiza

Key Differences

• Coastal Ragweed is Least Concern while Rootless Duckweed is Endangered.

Taxonomic Classification

Rank	Coastal Ragweed	Rootless Duckweed
Kingdom same	Plantae (พืช)	Plantae (พืช)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class	Magnoliopsida (พืชใบเลี้ยงคู่)	Liliopsida (Monocots)
Order	Asterales (อันดับทานตะวัน)	Alismatales (อันดับขาเขียด)
Family	Asteraceae (Daisy Family)	Araceae
Genus	Ambrosia	Wolffia
Species	Ambrosia hispida	Wolffia arrhiza

Evolutionary Relationship

Coastal Ragweed and Rootless Duckweed share a common ancestor at the Phylum level: Magnoliophyta. (Flowering Plants)

Conservation Status

Coastal Ragweed

LC — Least Concern

Rootless Duckweed

EN — Endangered

Physical Characteristics

Attribute	Coastal Ragweed	Rootless Duckweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Coastal Ragweed

Habitat

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

Range

Found in Cuba.

Rootless Duckweed

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, temperate broadleaf and mixed forests, and temperate coniferous forests, among 4 distinct biome types spanning the Indomalayan and Oceanian and Palearctic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Asia (Japan), Europe (10 countries), North America (Canada), and South America (Brazil). Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

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.