Phlebodium aureum 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 , and northern and eastern South America to Paraguay. It is the only species of Phlebodium found in North America, the other ten or so species all confined to South America. Other common names include Calaguala (among Spanish speaking peoples), Kalawalla, Samambia, and Anapsos.
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
Phlebodium aureum is well-adapted to cultivation and is valued both as an ornamental plant and in herbal medicine.
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.
It has been shown to be effective when administered orally as an immunomodulator (selectively modulates overactive immune cells), antipsoriatic, neuroprotective (protects brain cells), cough suppressant, anti-inflammatory, and ultraviolet light protectant. It has been commercially available since 1982 in Europe, and as yet has had no toxicity reports, although it may enhance the effects of digoxin and/or other digoxin-type prescription heart drugs.
Its uses include:
for psoriasis and other skin conditions
for Alzheimer's disease, dementia, and memory problems
for coughs, bronchitis, chest colds, and other upper respiratory problems
for autoimmune disorders
It is also reported to have been an aid for those with Multiple Sclerosis and Vitiligo.
A common registered brand includes Heliocare based in Spain. Additionally US patents have been granted for various processes for producing extracts.
Flora of North America: Phlebodium aureum
Germplasm Resources Information Network: Phlebodium aureum
Copeland, E. B. 1947. Genera Filicinum. The Genera of Ferns. Chronica Botanica. Waltham, Mass.
Lellinger, D.B. 1985. A Field Manual of the Ferns & Fern-allies of the United States & Canada. Smithsonian. Washington DC.
Studlar, S. M. 2006. Phlebodium aurem. Biology Department. West Virginia University.
Botanical Dermatology Database: Phlebodium aureum
New Sunscreens Promise Advances in Protection
MedlinePlus: Polypodium leucotomos extract and anapsos
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