Lygodium

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Lygodium
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Lygodium japonicum
Scientific classification
Kingdom:
Division:
Class:
Polypodiopsida /
 Pteridopsida (disputed)
Order:
Family:
Lygodiaceae

Genus:
Lygodium

Species

See text

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Lygodium (climbing fern) is a genus of about 40 species of ferns, native to tropical regions across the world, with a few temperate species in eastern Asia and eastern North America. It is the sole genus in the family Lygodiaceae, though included in the family Schizaeaceae by some botanists.

They are unusual in that the rachis, or midrib, of the frond is thin, flexible, and long, the frond unrolling with indeterminate growth and the rachis twining around supports, so that each frond forms a distinct vine. The fronds may be from 3-12 m long, depending on the species.

Some Lygodium species are now considered very problematic invasive weeds in the southeastern United States. Populations of Lygodium have increased more than 12-fold over the past decade, as noted by Florida's Institute of Food and Agricultural Sciences.[1]

Japanese climbing fern (Lygodium japonicum) was added to the Florida Noxious Weed List in 1999. It is also a major problem in pine plantations, causing contamination and harvesting problems for the pine straw industry. Old World climbing fern (Lygodium microphyllum) infests cypress swamps and other hydric sites, forming a monoculture. This massive infestation displaces all native flora and fauna, completely changing the ecosystem of the area.[2]

Plants in this genus have basal chromosome counts of n=28, 29, 30.

Extracts

The aqueous ethanol extract of spores of Lygodium japonicum showed in vitro testosterone 5α-reductase inhibitory activity and in vivo anti-androgenic activity using growth of flank organ in castrated Syrian hamsters and hair regrowth after shaving in testosterone-treated C57Black/6CrSlc mice. From the lipophilic constituents of the spores, the common fatty acids oleic acid, linoleic acid and palmitic acid were identified as the main active principles inhibiting testosterone 5α-reductase.[3]

Selected species

References and External Links

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