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Dryopteris expansa - (C.Presl.)Fraser-Jenkins&Jermy.

Spiny Wood Fern

Author	(C.Presl.)Fraser-Jenkins&Jermy.	Botanical references	200
Family	Dryopteridaceae	Genus	Dryopteris
Synonyms	Dryopteris assimilis - S. Walker.
Known Hazards	Although we have found no reports for this species, a number of ferns contain carcinogens so some caution is advisable[200]. 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[172]. 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.
Range	Northern Temperate Zone, including Britain.
Habitat	Cool moist woods, often on rotting logs and tree stumps[256].
Edibility Rating	2 (1-5)	Medicinal Rating	3 (1-5)

Physical Characteristics

Fern growing to 0.4m by 0.5m.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils. The plant prefers acid and neutral soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It requires moist soil.

Habitats

Woodland Garden; Dappled Shade; Shady Edge; Deep Shade;

Edible Uses

Edible Parts: Leaves; Root.

Root - raw or cooked[256]. Baked and then peeled before being eaten[257]. The raw root is rather bitter but they develop a sweet taste when cooked and are said by some people to develop a flavour rather like sweet potatoes[256]. The root is best harvested in early autumn. At this time the rhizomes are surrounded by scaly, finger-like projections - if the projections are flat and dark inside then the rhizomes are not good to eat but if they are round, fleshy and light-coloured then they can be eaten[256]. The young shoots, harvested in spring before they have fully unfurled, can be cooked and eaten[257]. They can be added to soups[257].

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Anthelmintic; Poultice.

A poultice of the pounded roots has been applied to cuts[257]. We have no other reports for this species, but the following uses apply to many members of this genus and quite probably also to this species[K]. The root contains ‘filicin’, a substance that paralyses tapeworms and other internal parasites and has been used as a worm expellent[4, 172, 238]. 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[238]. An oily purge, such as caster oil, increases the absorption of the fern root and can be dangerous[238]. The root is harvested in the autumn and can be dried for later use, it should not be stored for longer than 12 months[238]. This remedy should be used with caution and only under the supervision of a qualified practitioner[238]. The root is toxic and the dosage is critical[238]. See also the notes above on toxicity. The root is also used in the treatment of dandruff[4, 172].

Other Uses

Hair.

An infusion of the leaves has been used as a hair wash[257].

Cultivation details

An easily grown plant[233], it prefers an acid to neutral soil, succeeding in ordinary fertile soil in a shady position[175, 200]. Prefers a moist soil[188]. Closely related to D. dilatata and hybridising where their ranges meet to produce D. x ambroseae. Members of this genus are rarely if ever troubled by browsing deer[233].

Propagation

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.

Links

References

[K] Ken Fern
Notes from observations, tasting etc at Plants For A Future and on field trips.

[4] Grieve. A Modern Herbal. Penguin 1984 ISBN 0-14-046-440-9
Not so modern (1930's?) but lots of information, mainly temperate plants.

[172] Schofield. J. J. Discovering Wild Plants - Alaska, W. Canada and the Northwest. 0
A nice guide to some useful plants in that area.

[175] Bird. R. (Editor) Focus on Plants. Volume 5. (formerly 'Growing from seed') Thompson and Morgan. 1991
Very readable magazine with lots of information on propagation. A good article on Corydalis spp.

[188] Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990 ISBN 0-86318-386-7
Excellent range of photographs, some cultivation details but very little information on plant uses.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992 ISBN 0-333-47494-5
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.

[233] Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990 ISBN 0 460 86048 8
A concise guide to a wide range of perennials. Lots of cultivation guides, very little on plant uses.

[238] Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995 ISBN 0-7513-020-31
A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant.

[256] Turner. N. J. Food Plants of Coastal First Peoples UBC Press. Vancouver. 1995 ISBN 0-7748-0533-1
Excellent little handbook about the native food plants of Western Canada. Good descriptions of the plants and their uses with colour photos of most plants.

[257] Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998 ISBN 0-88192-453-9
Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.

Readers Comments

Plants for a Future does not verify the accuracy of reader comments, use at your own risk. In particular Plants For A Future can not take any responsibility for any adverse effects from the use of plants. You should always consult a professional before using plants medicinally.

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