''Phlebodium aureum'' (golden polypody, golden serpent fern, cabbage palm fern, gold-foot fern, blue-star fern, hare-foot fern; syn. ''Polypodium aureum'', ''Polypodium leucotomos'') is an epiphytic

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

native to tropical and subtropical regions of the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North America, North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. ...

Description

It is a

rhizomatous In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow ho ...

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

frond A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the lar ...

s 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 botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

in areas with year-round rainfall, semi-evergreen or briefly

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

in areas with a marked

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The ...

Distribution

It is confined to the eastern side of the continents, extending north into the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

and the extreme southeast of

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

, and south through the

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...

(the

Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the a ...

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and unincorporated ...

, and

Lesser Antilles The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc be ...

), and northern and eastern

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to t ...

. It is the only species of ''

Phlebodium ''Phlebodium'' is a small genus of ferns in the family Polypodiaceae, subfamily Polypodioideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). It is native to tropical and subtropical regions of the Americas.F ...

'' found in North America; the other species are all confined to South America.

Habitat

This fern is rarely terrestrial in habitat, usually colonizing the canopies of tropical

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

s and the dwarf palms of subtropical forests. It is common in the

cloud forests A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest (TMCF), is a generally tropical or subtropical, evergreen, montane, moist forest characterized by a persistent, frequent or seasonal low-level clo ...

of the Caribbean and northern South America. It grows in varied habitats in Florida, including

swamps A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

and

hammocks A hammock (from Spanish , borrowed from Taíno and Arawak ) is a sling made of fabric, rope, or netting, suspended between two or more points, used for swinging, sleeping, or resting. It normally consists of one or more cloth panels, or a wove ...

, 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

frost Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a g ...

s. High levels of light are also critical for the 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 Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...

and in

herbal medicine Herbal medicine (also herbalism) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. With worldwide research into pharmacology, some herbal medicines have been translated into modern remedie ...

. It can be cultivated in greenhouses in non-tropical climates if night temperatures do not fall below about 5 °C. Several

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

s 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.

Medicine

Decoctions have been used as a

panacea In Greek mythology, Panacea (Greek ''Πανάκεια'', Panakeia), a goddess of universal remedy, was the daughter of Asclepius and Epione. Panacea and her four sisters each performed a facet of Apollo's art: * Panacea (the goddess of univers ...

in Central American folk medicine. These tonics were prescribed for a multitude of ailments, ranging from

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...

heart disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, h ...

. Modern medicine has also investigated ''P. aureum'', often using the deprecated synonym ''Polypodium leucotomos''. Oral consumption of ''Polypodium leucotomos'' extract has also been studied for the treatment of dermatologic disorders including melasma, vitiligo, psoriasis, polymorphous light eruption, atopic dermatitis, postinflammatory hyperpigmentation, photoaging and skin cancer. Oral consumption of ''Polypodium leucotomos'' extract has been shown to protect the skin from ultraviolet light damage. Clinical studies have shown that ''Polypodium leucotomos'' extract provides photoprotection against the effects of both UVB and UVA light. A review of 19 human and 6 basic scientific studies showed that ''Polypodium leucotomos'' was well tolerated with a favorable side effect profile. Consequently, ''Polypodium leucotomos'' supplementation has been posited as an adjunct photoprotection strategy in combination with traditional UV filters, such as sunscreen.

Systematics

''Phlebodium aureum'' is a member of a very small, and recently discovered genus. It was split from the genus ''Polypodium'', and the split is still apparent in the multitude of synonyms available for ''Phlebodium aureum''. ''Phlebodium'' is one of the 178 genera in the family Polypodiaceae. Additionally, the family Polypodiaceae is broken into a number of subfamilies, with ''Phlebodium'' a member of the non-grammatid tribe within the subfamily

Polypodioideae Polypodioideae is a subfamily belonging to the fern family Polypodiaceae, which is a member of the suborder Polypodiineae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the subfamily may be treated as th ...

. Members of the non-grammatids in this subfamily include the genera ''Phlebodium'' as well as ''Polypodium'', from which ''Phlebodium'' is derived and which most likely is its closest relative. Other members include ''

Pecluma ''Pecluma'' is a genus of ferns in the family Polypodiaceae, subfamily Polypodioideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). They are called rockcap ferns. Species , ''Checklist of Ferns and Lycoph ...

'', ''

Pleopeltis ''Pleopeltis'' is a genus of ferns in the family Polypodiaceae, subfamily Polypodioideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). The genus widely distributed in tropical regions of the world, and also ...

'', '' Microgramma'', and ''

Pleurosoriopsis ''Pleurosoriopsis'' is a genus of ferns in the family Polypodiaceae, subfamily Polypodioideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). The genus has only one species, ''Pleurosoriopsis makinoi'', native ...

''. A bootstrapping technique proves that, at a 90% confidence level, the polypodiaceous ferns form a sister relationship with tree ferns. However, further phylogenetic studies need to be conducted regarding the current status of the genus, and which of the species are the most related. The genus ''Phlebodium'' is exemplified by containing rows of areoles that lack included veins, and each sorus served by two different veins. Correll and Correll, two authors responsible for thirty years of classification since Flora was introduced in 1982, documented ''Phlebodium aureum'' as ''Polypodium aureum'' as recently as 1982. However, this creation of the new genera is warranted based on some notable differences. For instance, Giudice et al. points out that the sori on ''Phlebodium'' are more smooth and rounded when compared to other groups within the family Polypodiaceae. Additionally, studies on spores and size of the mature plant prove that ''Phlebodium'' contrasts severely from the rest of its family, providing the creation of the genera. The division of genera within the Polypodiaceae is fairly gray, considering that systematically, gametophytes differ only very slightly amongst different genera. Members of the family Polypodiaceae are most closely related to the Davalliaceae, with further relationships noted to Oleandraceae,

Tectariaceae Tectariaceae is a family of leptosporangiate ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Polypodiineae. Alternatively, it may be treated as the ...

, and the Lomariopsidaceae within the order

Polypodiales The order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including tropical, semitropical and temperate areas. Description Polypodiale ...

, which contains 80% of today’s ferns species (see additional page for picture). The order arose and diversified about 100 million years ago, and are regarded as one of the most evolutionarily advanced orders of ferns.

References

External links

Flora of North America: ''Phlebodium aureum''