Polypodium vulgare

Polypodium vulgare
File:Polypodium vulgare-NF.jpg
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Polypodiopsida / Pteridopsida (disputed)
Order:	Polypodiales
Family:	Polypodiaceae
Genus:	Polypodium
Species:	P. vulgare
Binomial name
Polypodium vulgare L.

Polypodium vulgare, the common polypody, is a fern of the Polypodiaceae family.

Polypody has traditional uses in cooking for its aroma and sweet taste, and in herbal medicine as a purgative and vermifuge.

Description

Polypodium vulgare, the common polypody, is a fern developing in isolation from along a horizontal rhizome. The fronds with triangular leaflets measure 10 to 50 centimetres. They are divided all the way back to the central stem in 10 to 18 pairs of segments or leaflets.

The leaflets become much shorter at the end of the frond. The leaflets are generally whole or slightly denticulated and somewhat wider at their base, where they often touch each other. They have an alternating arrangement, those on one side being slightly offset from those on the other side. The petioles have no scales.

The sori are found on the lower side of the fronds and range in colour from bright yellow to orange. They became dark grey at maturity.

• Period of sporulation: July to September.
• Mode of dissemination: anemochory (wind dispersal).

P. vulgare is an allotetraploid species of hybrid origin, its parents being the diploids Polypodium appalachianum and Polypodium glycyrrhiza.

Geographical distribution

The common polypody occurs throughout western Europe, North Africa and Eastern North America.[1] It is very common in France, where it is found up to an altitude of 2,000 metres (6,600 ft). It is also quite common in Scandinavia and Carpathian Mountains. It is an introduced species in New Zealand, that has begun to spread into the wild as an invasive species.

Habitat

This fern is found in shaded and semi-shaded locations. It is found on old walls, cracks in rocks, the bases of trees and in rocky undergrowth. It prefers sandy soils and rarely tolerates lime.

Uses

• In cooking: The rhizome has a bittersweet taste. It has traditionally been used in some confectionery such as nougat for its aromatic properties. In 1971, a saponin, osladin was found in the roots and believed to be the compound responsible for the sweet taste as it elicits a relative sweetness 500 times sweeter than sugar (by weight).
• Medicinal: The dried rhizome is used in herbal medicine as a purgative and vermifuge; these properties are due to the phytoecdysteroids in the rhizome.

• Sycamore and epiphytic ferns.JPG

  A Sycamore covered with epiphytic Common Polypody ferns.
• Polypodium vulgare jfg.jpg

  Polypodium vulgare

• Illustration Polypodium vulgare0.jpg

  Polypodium vulgare, illustration

• Polypodium vulgare0.jpg

  Polypodium vulgare, sorus detail

Note

• The name Polypodium vulgare is sometimes applied to the Polypodium virginianum (rock polypody). Licorice fern is also known as Polypodium glycyrrhiza.

Further reading

• Plants of the Pacific Northwest Coast. Copyright 1994. Jim Pojar and Andy MacKinnon. Lone Pine Publishing, Vancouver, BC.
• Ecan.govt.nz - Common Polypody
• CT-botanical-society.org: Polypodium vulgare - Polypodium virginianum

External links

• Den virtuella floran: Polypodium vulgare (Swedish)

• (English) J Jizba, L Dolejs, V Herout & F Sorm, "The structure of osladin — The sweet principle of the rhizomes of Polypodium vulgare L.", in Tetrahedron Lett., vol. 18, 1971, p. 1329-1332. DOI 10.1016/S0040-4039(01)96701-2