vs Coastal Ragweed

Chrysothrix candelaris compared with Ambrosia hispida

Taxonomic Classification

Rank		Coastal Ragweed
Kingdom	Fungi (Fungi)	Plantae (Plants)
Phylum	Ascomycota (Sac Fungi)	Magnoliophyta (Flowering Plants)
Class	Arthoniomycetes (Arthoniomycetes)	Magnoliopsida (Dicots)
Order	Arthoniales (Arthoniales)	Asterales (Daisies & Sunflowers)
Family	Chrysotrichaceae	Asteraceae (Daisy Family)
Genus	Chrysothrix	Ambrosia
Species	Chrysothrix candelaris	Ambrosia hispida

Conservation Status

LC — Least Concern

Coastal Ragweed

LC — Least Concern

Physical Characteristics

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

Habitat & Geographic Range

Habitat

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

Range

Found across Europe (4 countries) and South America (Brazil, Colombia).

Coastal Ragweed

Habitat

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

Range

Found in Cuba.

Chrysothrix candelaris, commonly known as the gold dust lichen or egg yolk lichen, is a distinctive sorediate crustose lichen formed by the mutualistic association of a fungal partner (Chrysothrix candelaris, class Arthoniomycetes) with green algal photobionts. The lichen is immediately recognizable by its bright chrome-yellow to yellow-orange powdery soredia — granular reproductive propagules — which form a continuous farinose crust on the bark of acidic-barked trees, rock surfaces, and decaying wood in shaded, humid conditions. The vivid yellow color is due to calycin and other xanthone pigments. C. candelaris is widely distributed across Europe, North America, and South America, growing on smooth-barked deciduous and coniferous trees, boulders, and cliff faces in woodland and boreal forest habitats. It is assessed as Least Concern by the IUCN, reflecting its broad distribution and tolerance of a range of microhabitats. The lichen serves as a bioindicator of old-growth forest conditions and is sometimes used in air quality monitoring, as it is moderately sensitive to sulfur dioxide pollution. C. candelaris reproduces vegetatively through the dispersal of soredia by wind, water, and animals, which carry photobiont and mycobiont cells together.

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.