Coastal Ragweed vs Western Thyme Plume

Ambrosia hispida compared with Merrifieldia tridactyla

Key Differences

• Coastal Ragweed is Least Concern while Western Thyme Plume is Near Threatened.

Taxonomic Classification

Rank	Coastal Ragweed	Western Thyme Plume
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Arthropoda (Arthropods)
Class	Magnoliopsida (Dicots)	Insecta (Insects)
Order	Asterales (Daisies & Sunflowers)	Lepidoptera (Butterflies & Moths)
Family	Asteraceae (Daisy Family)	Pterophoridae
Genus	Ambrosia	Merrifieldia
Species	Ambrosia hispida	Merrifieldia tridactyla

Conservation Status

Coastal Ragweed

LC — Least Concern

Western Thyme Plume

NT — Near Threatened

Physical Characteristics

Attribute	Coastal Ragweed	Western Thyme Plume
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.

Western Thyme Plume

Habitat

Found across multiple habitat types including temperate coniferous forests, temperate broadleaf and mixed forests, and temperate grasslands and steppes, among 6 distinct biome types spanning the Indomalayan and Palearctic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Found across Asia (5 countries) and Europe (28 countries). Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

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.