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Common Name: Brittle Bladder Fern

General Information

Cystopteris fragilis is a Deciduous Fern up to 0.15 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[].
Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase[].

Botanical References

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Range

Cosmopolitan, found in most areas of the world, including Britain, but only on mountains in Tropics.

Habitat

Rocky woods, shady rocks and walls, especially on basic rocks, to 1200 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Deciduous Fern
Height	0.15 m
Cultivation Status	Wild

Cultivation Details

Prefers a shady position in a moist but well-drained soil, succeeding in most soil types[]. Plants can tolerate up to 4 hours direct sun per day[]. Prefers a pH between 6.5 and 7, but tolerates a range from 5.5 to 7.5[]. Plants do especially well when grown in a shaded position on old mortared walls[].
Members of this genus are rarely if ever troubled by browsing deer[].
Plants die back early in dry seasons[].
A very ornamental plant[].

Edible Uses

Root. An emergency food, it is only used when all else fails[].

Medicinal

A decoction of the roots has been used as an anthelmintic enema[].
A cold compound infusion of the plant has been used both internally and externally as a treatment for injury[].

Other Uses

Plants can be grown as a ground cover when planted out about 15cm apart each way[].

Propagation

Spores - best sown as soon as ripe on the surface of a humus-rich sterilized soil. Keep the compost moist, preferably by putting a plastic bag over the pot. Germinates in 1 - 3 months at 20°c[].Pot on small clumps of plantlets as soon as they are large enough to handle and keep humid until they are well established. Do not plant outside until the ferns are at least 2 years old.
Division in spring.