Coastal Ragweed vs Common Stonewort

Ambrosia hispida compared with Chara vulgaris

Key Differences

• Coastal Ragweed is Least Concern while Common Stonewort is Endangered.

Taxonomic Classification

Rank	Coastal Ragweed	Common Stonewort
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum	Magnoliophyta (Flowering Plants)	Charophyta (Charophyta)
Class	Magnoliopsida (Dicots)	Charophyceae (Charophyceae)
Order	Asterales (Daisies & Sunflowers)	Charales (Charales)
Family	Asteraceae (Daisy Family)	Characeae
Genus	Ambrosia	Chara
Species	Ambrosia hispida	Chara vulgaris

Evolutionary Relationship

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

Conservation Status

Coastal Ragweed

LC — Least Concern

Common Stonewort

EN — Endangered

Physical Characteristics

Attribute	Coastal Ragweed	Common Stonewort
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 Stonewort

Habitat

Native to Asia and Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Widely distributed across Asia (Taiwan), Europe (Denmark, Norway, Sweden), North America (United States), and South America (Brazil). Currently classified as 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 Stonewort

<em>Chara vulgaris</em>, the common stonewort, is a species of charophyte green alga in the family Characeae, order Charales. It typically grows submerged in freshwater habitats including ponds, lakes, ditches, and slow-moving streams, often forming dense mats on the substrate. The species has a broad geographic distribution spanning Asia, Europe, and the Americas, tolerating a range of water conditions from clear to moderately turbid. <em>Chara vulgaris</em> is notable for its heavily calcified, whorled structure that gives stoneworts their characteristic encrusted appearance and makes them valuable as paleoclimate indicators in sediment records. As a primary producer, it contributes to aquatic food webs and provides habitat for invertebrates and juvenile fish. Biological traits such as individual lifespan, precise growth rates, and specific consumer relationships remain poorly documented in the literature. Despite its wide range, <em>Chara vulgaris</em> is assessed as Endangered by the IUCN, reflecting significant population declines attributed to freshwater pollution, eutrophication, and habitat degradation across much of its range. Targeted conservation of clean, oligotrophic water bodies is essential for its persistence.