Coastal Ragweed vs Welsh onion

Ambrosia hispida compared with Allium fistulosum

Key Differences

• Coastal Ragweed is Least Concern while Welsh onion is Critically Endangered.

Taxonomic Classification

Rank	Coastal Ragweed	Welsh onion
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class	Magnoliopsida (Dicots)	Liliopsida (Monocots)
Order	Asterales (Daisies & Sunflowers)	Asparagales (Asparagales)
Family	Asteraceae (Daisy Family)	Amaryllidaceae
Genus	Ambrosia	Allium
Species	Ambrosia hispida	Allium fistulosum

Evolutionary Relationship

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

Conservation Status

Coastal Ragweed

LC — Least Concern

Welsh onion

CR — Critically Endangered

Physical Characteristics

Attribute	Coastal Ragweed	Welsh onion
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.

Welsh onion

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, deserts and xeric shrublands, and tropical and subtropical dry broadleaf forests, among 12 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (Algeria, Seychelles), Asia (Taiwan, Yemen), Europe (18 countries), North America (Canada, United States), Oceania and the Pacific (Tuvalu), and South America (Brazil, Colombia, Peru). Currently classified as Critically 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.