Brook Thistle vs Coastal Ragweed

Cirsium rivulare compared with Ambrosia hispida

Key Differences

• Brook Thistle is Extinct while Coastal Ragweed is Least Concern.

Taxonomic Classification

Rank	Brook Thistle	Coastal Ragweed
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class same	Magnoliopsida (Dicots)	Magnoliopsida (Dicots)
Order same	Asterales (Daisies & Sunflowers)	Asterales (Daisies & Sunflowers)
Family same	Asteraceae (Daisy Family)	Asteraceae (Daisy Family)
Genus	Cirsium	Ambrosia
Species	Cirsium rivulare	Ambrosia hispida

Evolutionary Relationship

Brook Thistle and Coastal Ragweed share a common ancestor at the Family level: Asteraceae. (Daisy Family)

Conservation Status

Brook Thistle

EX — Extinct

Coastal Ragweed

LC — Least Concern

Physical Characteristics

Attribute	Brook Thistle	Coastal Ragweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brook Thistle

Habitat

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

Range

Found across Europe (7 countries).

Coastal Ragweed

Habitat

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

Range

Found in Cuba.

Brook Thistle

The Brook Thistle (Cirsium rivulare) is a species in the genus Cirsium. It is currently classified as Extinct on the IUCN Red List. Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

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.