The Common Polypody (Polypodium vulgare) is a fern of the Polypodiaceae family.
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: anemochore (wind dispersal).
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 chalky soils and rarely tolerates lime.
The common polypody is very common in France, where it is found up to an altitude of 2000m. It is less commonly found around the Mediterranean. In the United States it is commonly found in the Pacific Northwest (especially Oregon and Washington) from coastal areas inland and throughout the Cascades.
- In cooking: The rhizome has a bittersweet taste. It has traditionally been used in some confectionary such as nougat for its aromatic properties.
- Medicinal: For 2000 years the dried root has been used to ward off parasites, as a laxative and an expectorant.
- The name Polypodium vulgare is sometimes applied to the Polypodium virginianum or Rock Polypody. Licorice Fern is also known as Polypodium glycyrrhiza.
- Plants of the Pacific Northwest Coast. Copyright 1994. Jim Pojar and Andy MacKinnon. Lone Pine Publishing, Vancouver, BC.