Practical
Plants

Dryopteris cristata

Crested Wood Fern

an evergreen member of the Dryopteris genus in the family Dryopteridaceae.

No photo available

Taxonomy and growth

Foliage
evergreen
Height
0.5 m
Spread
0.4 m

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

Although we have found no reports for this species, a number of ferns contain carcinogens so some caution is advisable[3]. The fresh plant contains 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[1]. However, there have been reports for other species of ferns suggesting that even cooked fronds can have a long term harmful effect. Some caution is therefore advised.

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

The male fern is one of the most popular and effective treatments for tape worms. The root stalks are anodyne, antibacterial, anti-inflammatory, antiviral, astringent, expectorant, febrifuge, sudorific, vermifuge and vulnerary[4][5][7]. The root contains 'filicin', a substance that paralyses tapeworms and other internal parasites and has been used as a worm expellent[7]. It is one of the most effective treatments known for tapeworms - its use should be immediately followed by a non-oily purgative such as magnesium sulphate in order to expel the worms from the body[7]. An oily purge, such as caster oil, increases the absorption of the fern root and can be dangerous[7]. The root is also taken internally in the treatment of internal haemorrhage, uterine bleeding, mumps and feverish illnesses[7]. The root is harvested in the autumn and can be dried for later use, it should not be stored for longer than 12 months[7]. This remedy should be used with caution and only under the supervision of a qualified practitioner[7]. The root is toxic and the dosage is critical[7]. See also the notes above on toxicity. Externally, the root is used in the treatment of abscesses, boils, carbuncles and sores[7].

Product or use
Diaphoretic
Product or use
Expectorant
Product or use
Febrifuge
Product or use
Vermifuge

Environment

Range
Eastern N. America - Newfoundland to Saskatchewan and south to N. Carolina and Montana.
Habitat
Damp woods[5]. Swamps, swampy woods or open shrubby wetlandsfrom sea level to 1200 metres[8].
Shade tolerance
partial shade
Water
moderate
Hardiness
Zone 4+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral
Tolerances
drought
Tolerates Nutritionally Poor Soil
No
Drought
tolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Spores - can be sown at any time of the year in a greenhouse. Surface sow on a sterilised compost and keep moist, possibly by placing the pot in a plastic bag. Germinates in 1 - 3 months at 20°c. Pot up small clumps of the plants when they are large enough to handle and grow on in a shady part of the greenhouse until large enough to plant out. Division in spring. Larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

Prefers an acid to neutral soil, succeeding in ordinary fertile soil in a shady position. Succeeds in full sun but grows best in a shady position with only 2 - 3 hours sun per day[3]. Tolerates a pH range from 4.5 to 7[3]. Dislikes heavy clay. Prefers a good supply of water at its roots but succeeds in dry shade and tolerates drought when it is established. A very hardy plant, tolerating temperatures down to about -30°c[3]. Members of this genus are rarely if ever troubled by browsing deer[6]. Hybridizes in the wild with several other species[2].

References

  1. Schofield. J. J. Discovering Wild Plants - Alaska, W. Canada and the Northwest.

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  2. Phillips. R. & Rix. M. Perennials Volumes 1 and 2. Pan Books 1991-00-00 ISBN 0-330-30936-9

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  3. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4

  4. Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. 1985-00-00 ISBN 0-917256-20-4

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  5. Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. 1990-00-00 ISBN 0395467225

    ↩1↩2

  6. Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990-00-00 ISBN 0 460 86048 8

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  7. Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9

  8. Flora of N. America http://flora.huh.harvard.edu/fna/

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