Coast Sandbur vs Coastal Ragweed

Cenchrus spinifex compared with Ambrosia hispida

Key Differences

• Coast Sandbur is Not Evaluated while Coastal Ragweed is Least Concern.

Taxonomic Classification

Rank	Coast Sandbur	Coastal Ragweed
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class	Liliopsida (Monocots)	Magnoliopsida (Dicots)
Order	Poales (Grasses)	Asterales (Daisies & Sunflowers)
Family	Poaceae (Grass Family)	Asteraceae (Daisy Family)
Genus	Cenchrus	Ambrosia
Species	Cenchrus spinifex	Ambrosia hispida

Evolutionary Relationship

Coast Sandbur and Coastal Ragweed share a common ancestor at the Phylum level: Magnoliophyta. (Flowering Plants)

Conservation Status

Coast Sandbur

NE — Not Evaluated

Coastal Ragweed

LC — Least Concern

Physical Characteristics

Attribute	Coast Sandbur	Coastal Ragweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Coast Sandbur

Habitat

Typically found in grasslands, wetlands, forests, and cultivated landscapes.

Range

Widely distributed across Africa (Libya, South Africa), Asia (Turkey), Europe (Greece, Norway, Romania), North America (United States), and South America (Brazil, Colombia).

Coastal Ragweed

Habitat

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

Range

Found in Cuba.

Coast Sandbur

Coast sandbur (Cenchrus spinifex) is an annual or short-lived perennial grass in the family Poaceae, native to warm coastal regions of the Americas but now widespread as a weed throughout tropical and subtropical regions worldwide, including Africa, Australia, and parts of Asia. It grows on coastal dunes, sandy beaches, roadsides, disturbed ground, and the margins of agricultural land. The genus Cenchrus is notable for producing sharp, bur-like seed clusters enclosed in rigid, spine-tipped involucres that readily attach to animal fur, clothing, and footwear for dispersal—a highly effective mechanism for long-distance spread. Coast sandbur is considered a nuisance weed in recreational and agricultural settings due to its painful burs. It is tolerant of salt, drought, and nutrient-poor substrates, making it a successful coloniser of disturbed coastal environments. The IUCN conservation status is Not Evaluated. While not threatened in any way, coast sandbur presents challenges in areas where it has naturalised, competing with native beach and dune vegetation.

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.