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Common Name: Marginal Woodfern
Dryopteris marginalis is a Evergreen Fern up to 0.75 metres tall.
It has medicinal uses.
Although we have found no reports for this species, a number of ferns contain carcinogens so some caution is advisable[
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[
]. 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.
N. America - Canada to Georgia and westwards to the Rockies.
Damp woods and swamps[
]. Rocky, wooded slopes and ravines, edges of woods, stream banks and roadbanks, and rock walls at elevations of 50 - 1500 metres[
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[
]. Tolerates a pH range from 4.5 to 7[
]. 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[
Members of this genus are rarely if ever troubled by browsing deer[
Hybridizes in the wild with several other species[
The root contains ‘filicin’, a substance that paralyses tapeworms and other internal parasites and has been used as a worm expellent[
]. 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[
]. An oily purge, such as caster oil, increases the absorption of the fern root and can be dangerous[
]. The root is harvested in the autumn and can be dried for later use, it should not be stored for longer than 12 months[
]. This remedy should be used with caution and only under the supervision of a qualified practitioner[
]. The root is toxic and the dosage is critical[
]. See also the notes above on toxicity.
An infusion of the root has been used in the treatment of rheumatism[
]. A warm infusion, held in the mouth, has been used to treat toothaches[
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.