The Polypodiaceaefamily contains more than60 genera andapproximately 1,000 species of fern plants. Most of them are epiphytes (organisms that live attached to a live plant, yet they do not parasitize on it).
In this family the reproductive organs – sporangia, are gathered in groups (sori) of different sizes.They originate in the plant tissue and are attached to the lower surface of the leaves. Each sporangium is formed in the division of a solitary epidermal cell and consists of a small capsule.
Quite characteristic is the small ring (annulus)which, together with the cells of the labium and through a cohesion mechanism opens the sporangia and throws out the spores.A typical member of the familyis thePolypodium vulgare L. It is a species of perennial evergreen fern plantabundantly growing in shady areas in woods and among rocks. The leaves vary in length and sharpness of the peak.They grow from a stem resembling a root that climbs to the surface of the soil or immediately beneath it. The capsules of the spores grow in two lines on both sides of the central vein on the inferior side of the leaves.They are ideally round mounds without a cover (indusial). When they ripen they acquire a yellowish or light orange hue. The roots of this fern are very sweet and pleasant to taste.This has given its commonly used name ‘sweet’ fern.