Brittle Bladderfern vs Coastal Ragweed

Cystopteris tenuis compared with Ambrosia hispida

Key Differences

• Brittle Bladderfern is Not Evaluated while Coastal Ragweed is Least Concern.

Taxonomic Classification

Rank	Brittle Bladderfern	Coastal Ragweed
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum	Tracheophyta	Magnoliophyta (Flowering Plants)
Class	Polypodiopsida (Polypodiopsida)	Magnoliopsida (Dicots)
Order	Polypodiales (Polypodiales)	Asterales (Daisies & Sunflowers)
Family	Cystopteridaceae	Asteraceae (Daisy Family)
Genus	Cystopteris	Ambrosia
Species	Cystopteris tenuis	Ambrosia hispida

Evolutionary Relationship

Brittle Bladderfern and Coastal Ragweed share a common ancestor at the Kingdom level: Plantae. (Plants)

Conservation Status

Brittle Bladderfern

NE — Not Evaluated

Coastal Ragweed

LC — Least Concern

Physical Characteristics

Attribute	Brittle Bladderfern	Coastal Ragweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brittle Bladderfern

Habitat

Typically found in moist, shaded forest floors and tropical canopies.

Range

Distributed across Canada and United States.

Coastal Ragweed

Habitat

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

Range

Found in Cuba.

Brittle Bladderfern

The Brittle Bladderfern (Cystopteris tenuis) is a species in the genus Cystopteris. Typically found in moist, shaded forest floors and tropical canopies.

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.