At a glance
Essentials
- Size
- Fronds 10 to 50 cm long. Leaflets 10–20 cm long and 5–7 cm wide. The range may vary with age, sex and population.
- Distribution
- Widely distributed in the temperate Northern Hemisphere: western Europe, North Africa, North America (especially the west coast), and parts of Asia. In New Zealand it is an introduced species.
- Habitat
- Rocky, shady areas, forests, walls, rock crevices, and as an epiphyte on mossy trees. It prefers substrates rich in organic matter and acidic.
- Activity
- Spore production from July to September. Spores are dispersed by wind (anemochory).
Observation guide
What to look for
- 01
Leathery, evergreen fronds, with entire or slightly toothed leaflets.
- 02
Circular sori, yellow to orange, arranged in two rows on the underside of the fronds.
- 03
Creeping rhizome, often thick and covered with dry scales.
Lighting, age and viewing angle can hide features. If identification affects consumption, handling or conservation, consult specialist sources.
Ecology
Description and characteristics
Polypodium vulgare is a perennial, evergreen fern in the family Polypodiaceae. It is characterized by a creeping rhizome, often thick and covered with dry scales, which extends over rocks, trunks or the ground and allows dense clumps to form. Its fronds, leathery in texture and dark green in color, measure 10 to 50 cm in length and are divided to the central axis into 10 to 18 pairs of segments or leaflets. These leaflets are generally entire or slightly toothed, wider at the base, and arranged alternately. On the underside of the fronds are sori, circular structures containing sporangia; they are bright yellow to orange and turn dark gray as they mature, arranged in two rows between the midrib and the edge of each segment. Spore production occurs between July and September, and the spores are dispersed by wind (anemochory). This species is an allotetraploid, resulting from a hybridization event and chromosome duplication, which explains its distinctive genetics and restriction to temperate regions of the north.