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Dryopteridaceae FAMILY

Dryopteris crassirhizoma

Dryopteris crassirhizoma

Edibility
1/5
Medicinal
4/5

Safety & Hazards

Although we have found no reports for this species, a number of ferns contain carcinogens so some caution is advisable[1]. 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[2]. 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.

Cultivation Details

HabitFern
Growth—

Prefers an acid to neutral soil, succeeding in ordinary fertile soil in a shady position[3, 1]. Prefers a moist soil[4], but is drought tolerant when well established[1]. Members of this genus are rarely if ever troubled by browsing deer[5].

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. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Dryopteris+crassirhizoma>

Pollinators

Data unavailable

References

  1. [1]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · 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.
  2. [2]Discovering Wild Plants - Alaska, W. Canada and the Northwest. — Schofield. J. J. · Alaska Northwest Books; Alaska · 2003 · ISBN 0882403699 ↩︎A nice guide to some useful plants in that area.
  3. [3]Focus on Plants. Volume 5. (formerly 'Growing from seed') — Bird. R. (Editor) · Thompson and Morgan. · 1991 · ISBN - ↩︎Very readable magazine with lots of information on propagation. A good article on Corydalis spp.
  4. [4]The RHS Gardener's Encyclopedia of Plants and Flowers — Brickell. C. · Dorling Kindersley Publishers Ltd. · 1990 · ISBN 0-86318-386-7 ↩︎Excellent range of photographs, some cultivation details but very little information on plant uses.
  5. [5]Perennial Garden Plants — Thomas. G. S. · 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.
  6. [6]Atlas of Medicinal Plants. — Kariyone. T. · Nihon Rinshosha; Osaka · 1973 ↩︎A good Japanese herbal.
  7. [7]Flora of Japan — http://www.foj.info ↩︎An on-line version of the flora - an excellent resource.
  8. [8]Plants for Human Consumption. — Kunkel. G. · Koeltz Scientific Books · 1984 · ISBN 3874292169 ↩︎An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
  9. [9]Encyclopaedia of Herbs and their Uses. — Bown. D. · 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.
  10. [10]Medicinal Plants in the Republic of Korea — World Health Organisation, Manila · 1998 · ISBN 92 9061 120 0 ↩︎An excellent book with terse details about the medicinal uses of the plants with references to scientific trials. All plants are described, illustrated and brief details of habitats given.
  11. [11]Medicinal Plants of China — Duke. J. A. and Ayensu. E. S. · Reference Publications, Inc. · 1985 · ISBN 0-917256-20-4 ↩︎Details of over 1,200 medicinal plants of China and brief details of their uses. Often includes an analysis, or at least a list of constituents. Heavy going if you are not into the subject.