Agulhas Spiderhead vs Coastal Ragweed

Serruria bolusii compared with Ambrosia hispida

Key Differences

• Agulhas Spiderhead is Near Threatened while Coastal Ragweed is Least Concern.

Taxonomic Classification

Rank	Agulhas Spiderhead	Coastal Ragweed
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class same	Magnoliopsida (Dicots)	Magnoliopsida (Dicots)
Order	Proteales (Proteales)	Asterales (Daisies & Sunflowers)
Family	Proteaceae	Asteraceae (Daisy Family)
Genus	Serruria	Ambrosia
Species	Serruria bolusii	Ambrosia hispida

Evolutionary Relationship

Agulhas Spiderhead and Coastal Ragweed share a common ancestor at the Class level: Magnoliopsida. (Dicots)

Conservation Status

Agulhas Spiderhead

NT — Near Threatened

Coastal Ragweed

LC — Least Concern

Physical Characteristics

Attribute	Agulhas Spiderhead	Coastal Ragweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Agulhas Spiderhead

Habitat

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

Coastal Ragweed

Habitat

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

Range

Found in Cuba.

Agulhas Spiderhead

The Agulhas Spiderhead (Serruria bolusii) is a species in the genus Serruria. It is currently classified as Near Threatened 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.