Coastal Ragweed vs Common Coontail

Ambrosia hispida compared with Ceratophyllum demersum

Taxonomic Classification

Rank	Coastal Ragweed	Common Coontail
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class same	Magnoliopsida (Dicots)	Magnoliopsida (Dicots)
Order	Asterales (Daisies & Sunflowers)	Ceratophyllales (Ceratophyllales)
Family	Asteraceae (Daisy Family)	Ceratophyllaceae
Genus	Ambrosia	Ceratophyllum
Species	Ambrosia hispida	Ceratophyllum demersum

Evolutionary Relationship

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

Conservation Status

Coastal Ragweed

LC — Least Concern

Common Coontail

LC — Least Concern

Physical Characteristics

Attribute	Coastal Ragweed	Common Coontail
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 Coontail

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, flooded grasslands and savannas, and deserts and xeric shrublands, among 9 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (4 countries), Asia (6 countries), Europe (8 countries), North America (4 countries), Oceania and the Pacific (4 countries), and South America (Brazil, Colombia).

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 Coontail

<em>Ceratophyllum demersum</em>, commonly known as common coontail or hornwort, is a submerged aquatic plant in the family Ceratophyllaceae. It has an almost cosmopolitan distribution, occurring on every continent except Antarctica in freshwater lakes, ponds, slow-moving rivers, and ditches. Common coontail is rootless, floating freely or loosely anchored in sediment, and forms dense underwater mats that provide important habitat and refuge for fish, invertebrates, and waterfowl. Its whorled, forked leaves are stiff and brittle with toothed margins. The species is well adapted to a wide range of water conditions and can tolerate turbid, nutrient-rich waters where other aquatic plants may struggle. It plays a significant role in aquatic ecosystems by oxygenating water and filtering excess nutrients. The species is assessed as Least Concern by the IUCN. Biological traits of this species remain poorly documented in the scientific literature.

Shared Countries

Both species can be found in 1 countries:

🇨🇺 Cuba