American Eelgrass vs Coastal Ragweed

Vallisneria americana compared with Ambrosia hispida

Taxonomic Classification

Rank	American Eelgrass	Coastal Ragweed
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class	Liliopsida (Monocots)	Magnoliopsida (Dicots)
Order	Alismatales (Alismatales)	Asterales (Daisies & Sunflowers)
Family	Hydrocharitaceae	Asteraceae (Daisy Family)
Genus	Vallisneria	Ambrosia
Species	Vallisneria americana	Ambrosia hispida

Evolutionary Relationship

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

Conservation Status

American Eelgrass

LC — Least Concern

Coastal Ragweed

LC — Least Concern

Physical Characteristics

Attribute	American Eelgrass	Coastal Ragweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

American Eelgrass

Habitat

Found across multiple habitat types including deserts and xeric shrublands, tropical and subtropical moist broadleaf forests, and tropical and subtropical grasslands and savannas, among 4 distinct biome types spanning the Palearctic and Neotropic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (Egypt), Asia (Taiwan), Europe (Belgium, Italy), North America (5 countries), and South America (Colombia).

Coastal Ragweed

Habitat

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

Range

Found in Cuba.

American Eelgrass

The American Eelgrass (Vallisneria americana) is a species in the genus Vallisneria. It is currently classified as Least Concern on the IUCN Red List. Found across multiple habitat types including deserts and xeric shrublands, tropical and subtropical moist broadleaf forests, and tropical and subtropical grasslands and savannas, among 4 distinct biome types spanning the Palearctic and Neo.

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.

Shared Countries

Both species can be found in 1 countries:

🇨🇺 Cuba