Coastal Ragweed vs Common Frillwort

Ambrosia hispida compared with Fossombronia pusilla

Key Differences

• Coastal Ragweed is Least Concern while Common Frillwort is Critically Endangered.

Taxonomic Classification

Rank	Coastal Ragweed	Common Frillwort
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum	Magnoliophyta (Flowering Plants)	Marchantiophyta (liverwort)
Class	Magnoliopsida (Dicots)	Jungermanniopsida (Jungermanniopsida)
Order	Asterales (Daisies & Sunflowers)	Fossombroniales (Fossombroniales)
Family	Asteraceae (Daisy Family)	Fossombroniaceae
Genus	Ambrosia	Fossombronia
Species	Ambrosia hispida	Fossombronia pusilla

Evolutionary Relationship

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

Conservation Status

Coastal Ragweed

LC — Least Concern

Common Frillwort

CR — Critically Endangered

Physical Characteristics

Attribute	Coastal Ragweed	Common Frillwort
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.

Common Frillwort

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, temperate broadleaf and mixed forests, and Mediterranean forests and woodlands spanning the Indomalayan and Palearctic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Found across Asia (Taiwan) and Europe (5 countries). 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.

Common Frillwort

<em>Fossombronia pusilla</em>, commonly known as the common frillwort, is a small liverwort belonging to the family Fossombroniaceae within the division Marchantiophyta. This non-vascular bryophyte typically grows in moist, disturbed soils, clay banks, and damp pathways across its range in Europe and parts of Asia. The thallus is typically lobed and frilly in appearance, giving the species its common name. <em>Fossombronia pusilla</em> favors habitats with high moisture and reduced competition, often colonizing bare or sparsely vegetated ground following disturbance. Its geographic range spans temperate regions of western and central Europe into Asia, though populations have become increasingly fragmented. The species is currently assessed as Critically Endangered on the IUCN Red List, reflecting severe population declines likely driven by habitat loss, land drainage, and agricultural intensification. Biological traits such as lifespan, body size, and diet remain poorly documented for this species, as is common among many small bryophyte taxa. Like other liverworts, <em>Fossombronia pusilla</em> reproduces both sexually through spores and vegetatively. Conservation of this species depends on protecting moist, low-competition microhabitats and reducing disturbance to its specialized substrates.