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Phlebodium aureum (golden polypody, golden serpent fern, cabbage palm fern, gold-foot fern, hare-foot fern; syn. Polypodium aureum, Polypodium leucatomos) is an epiphytic fern native to tropical and subtropical regions of the Americas. It is confined to the eastern side of the continents, extending north into the United States to Florida and the extreme southeast of Georgia, and south through the Caribbean (the Bahamas, Puerto Rico, and Lesser Antilles), and northern and eastern South America to Paraguay. It is the only species of Phlebodium found in North America, the other species all confined to South America. Other common names include calaguala (Spanish language), laua`e haole (Hawaiian), samambia, and hartassbräken (Swedish).
It is a rhizomatous fern, with the creeping rhizome 8–15 mm (rarely 30 mm) in diameter, densely covered in the golden-brown scales that give the species its name. The fronds are large and pinnatifid (deeply lobed), from 30–130 cm long and 10–50 cm broad, with up to 35 pinnae; they vary in color from bright green to glaucous green and have undulate margins. Several round sori run along each side of the pinna midrib, and the minute spores are wind-dispersed. The fronds are evergreen in areas with year-round rainfall, semi-evergreen or briefly deciduous in areas with a marked dry season.
This fern is rarely terrestrial in habitat, usually colonizing the canopies of tropical rainforests and the dwarf palms of subtropical forests. It is common in the cloud forests of the Caribbean and northern South America. It grows in varied habitats in Florida, including swamps and hammocks, and can thus apparently tolerate a wide range of microclimates. Its restriction to the tropics and subtropics is readily explained by its intolerance of anything other than very brief, light frosts. High levels of light are also critical for growth of this species, and its deciduous habit allows it to invade relatively dry areas.
Cultivation and uses
It can be cultivated in greenhouses in nontropical climates if night temperatures do not fall below about 5 °C. Several cultivars have been selected for garden planting, with varying leaf color from grey-green to silver-green to blue-green, or with cristate or very wavy frond margins.
Decoctions have been used as a panacea in Central American folk medicine. These tonics were prescribed for a multitude of ailments, ranging from asthma to heart disease. A close relative, Polypodium vulgare, was used historically in Europe up to the Renaissance to relieve coughing and treat mental illness. Its use as a tea for blood cleansing began with the Mayans, and continues today in Honduran culture. Orally administered extracts have been effective immunomodulators, antipsoriatics, neuroprotective agents, cough suppressants, and anti-inflammatories in laboratory studies. An extract may also protect skin from ultraviolet damage.
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- Phlebodium aureum in BoDD – Botanical Dermatology Database