Narrow Buckler Fern, Spinulose woodfern

Dryopteris carthusiana

Physical Characteristics

Dryopteris carthusiana is a FERN growing to 1 m (3ft 3in) by 0.5 m (1ft 8in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 5. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid and neutral soils. It can grow in semi-shade (light woodland). It prefers moist or wet soil.

Distribution

Europe, including Britain, from Scandanavia south and east to Spain and Siberia. N. America..

Habitats

Woodland Garden Dappled Shade; Shady Edge; Ground Cover; Bog Garden;

Edible Uses

Edible Parts: Leaves Root Edible Uses: Root - baked[61]. Some caution is advised, see notes above on toxicity. Old leafstalks on the underground stems can be roasted, peeled and the inner portion eaten[257]. Young curled fronds, harvested as they are developing in the spring, can be boiled and eaten like asparagus[257].

Medicinal Uses

Vermifuge The root contains ‘filicin’, a substance that paralyses tapeworms and other internal parasites and has been used as a worm expellent[4, 222, 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.

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.