Practical
Plants

Dryopteris dilatata

Shield Fern

a member of the Dryopteris genus in the family Dryopteridaceae.

No photo available

Taxonomy and growth

Height
1.2 m
Spread
0.5 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[8]. 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[4]. 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.

Edible uses

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

Young fronds - they must be cooked[172. Some caution is advised, see the notes above on toxicity. Root - cooked[1][2][6]. Harvested in the spring and baked[10].

Plant part
Leaves
Plant part
Root

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 root contains 'filicin', a substance that paralyses tapeworms and other internal parasites and has been used as a worm expellent[13][4][12]. 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[12]. An oily purge, such as caster oil, increases the absorption of the fern root and can be dangerous[12]. The root is harvested in the autumn and can be dried for later use, it should not be stored for longer than 12 months[12]. This remedy should be used with caution and only under the supervision of a qualified practitioner[12]. The root is toxic and the dosage is critical[12]. See also the notes above on toxicity. The root is also used in the treatment of dandruff[13][4].

Product or use
Antidandruff
Product or use
Vermifuge

Material uses

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

An infusion of the fronds is used as a hair rinse and to treat dandruff[4][10]. The leaves can be used as a packing material for fruit etc[4]. Plants can be grown as a ground cover when spaced about 60cm apart each way[9].

Product or use
Hair care
Product or use
Packing

Ecology and functions

Ecosystem niche
Soil surface

Environment

Range
Europe, including Britain, Iceland and N. Russia south and east to Spain and temperate Asia.
Habitat
Woods, hedgebanks, wet heaths, shady rock ledges and crevices[3].
Shade tolerance
partial shade
Water
moderate
Hardiness
Zone 5+
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.

An easily grown plant[11], it prefers an acid to neutral soil, succeeding in ordinary fertile soil in a shady position[5][8]. Prefers a moist soil[7], but is drought tolerant when well established[8]. Plants are evergreen in mild winters[7]. Members of this genus are rarely if ever troubled by browsing deer[11].

References

  1. Gunther. E. Ethnobotany of Western Washington. University of Washington Press 1981-00-00 ISBN 0-295-95258-X

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  2. Yanovsky. E. Food Plants of the N. American Indians. Publication no. 237. U.S. Depf of Agriculture.

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  3. Clapham, Tootin and Warburg. Flora of the British Isles. Cambridge University Press 1962-00-00

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

    ↩1↩2↩3↩4↩5

  5. Bird. R. (Editor) Focus on Plants. Volume 5. (formerly 'Growing from seed') Thompson and Morgan. 1991-00-00

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  6. Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984-00-00 ISBN 3874292169

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  7. Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990-00-00 ISBN 0-86318-386-7

    ↩1↩2

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

    ↩1↩2↩3

  9. Thomas. G. S. Plants for Ground Cover J. M. Dent & Sons 1990-00-00 ISBN 0-460-12609-1

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  10. Weiner. M. A. Earth Medicine, Earth Food. Ballantine Books 1980-00-00 ISBN 0-449-90589-6

    ↩1↩2

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

    ↩1↩2

  12. 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

  13. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2

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