Practical
Plants

Dioscorea japonica

Glutinous Yam

a deciduous vegetable vine of the Dioscorea genus in the family Dioscoreaceae.

No photo available

Taxonomy and growth

Life cycle
perennial
Woodiness
woody
Fertility
self sterile
Flower type
dioecious

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.

Edible species of Dioscorea have opposite leaves whilst poisonous species have alternate leaves[2].

Edible uses

The tubers, vine tips and bulbils (small tuber-like growths on the vine) are edible.

Plant part
Tuber
Preparation
Cooked
Product or use
Food
Plant part
Vine tips
Preparation
Cooked
Product or use
Food
Plant part
Bulbils
Preparation
Cooked, boiled, steamed
Product or use
Food

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 tubers are prescribed in the treatment of diarrhoea, enteritis, enuresis and spermatorrhoea[9]. They are also dried and cut into shavings then used as a tonic[9]. The roots of most, if not all, members of this genus, contains diosgenin[11][12]. This is widely used in modern medicine in order to manufacture progesterone and other steroid drugs. These are used as contraceptives and in the treatment of various disorders of the genitary organs as well as in a host of other diseases such as asthma and arthritis[11].

Product or use
Contraceptive
Product or use
Miscellany
Product or use
Tonic

Ecology and functions

Ecosystem niche
Climber

Environment

Range
E. Asia - China, C. and S. Japan.
Habitat
Wooded foothills[15]. Mixed forests and margins, scrub forests, herb communities, mountain slopes, valleys, along rivers and streams, roadsides; 100 - 1200 metres[13].
Light
full sun
Shade tolerance
no shade
Water
moderate
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

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

Seed - sow March to April in a sunny position in a warm greenhouse and only just cover. It germinates in 1 - 3 weeks at 20°c[3]. Prick out the seedlings as soon as they are large enough to handle and grow on in a greenhouse for their first year. Plant out in late spring as the plant comes into new growth. Basal stem cuttings in the summer[14]. Division in the dormant season, never when in growth[1]. The plant will often produce a number of shoots, the top 5 - 10 cm of the root below each shoot can be potted up to form a new plant whilst the lower part of the root can be eaten[K]. Tubercles (baby tubers) are formed in the leaf axils. These are harvested in late summer and early autumn when about the size of a pea and coming away easily from the plant. They should be potted up immediately in individual pots in a greenhouse or cold frame. Plant out in early summer when in active growth[K].

Cultivation

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

We have very little information on this species and do not know if it will be hardy in Britain, though judging by its native range it could succeed outdoors at least in the mildest areas of this country. The following notes are based on the general needs of the genus. Easily grown in a fertile well-drained soil in a sunny position or light shade[8]. Prefers a rich light soil[1]. Plants produce tubercles (small tubers that are formed in the leaf axils of the stems), and can be propagated by this means[K]. A climbing plant that supports itself by twining around the branches of other plants[10]. Dioecious. Male and female plants must be grown if seed is required.

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩1↩2

  2. Kariyone. T. Atlas of Medicinal Plants.

    ↩

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

    ↩

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

  5. Reid. B. E. Famine Foods of the Chiu-Huang Pen-ts'ao. Taipei. Southern Materials Centre 1977-00-00

  6. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

  7. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

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

    ↩

  9. Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. 1985-00-00 ISBN 0-917256-20-4

    ↩1↩2

  10. Grey-Wilson. C. & Matthews. V. Gardening on Walls Collins 1983-00-00 ISBN 0-00-219220-0

    ↩

  11. Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. 1990-00-00 ISBN 0395467225

    ↩1↩2

  12. Chopra. R. N., Nayar. S. L. and Chopra. I. C. Glossary of Indian Medicinal Plants (Including the Supplement). Council of Scientific and Industrial Research, New Delhi. 1986-00-00

    ↩

  13. Flora of China 1994-00-00 http://flora.huh.harvard.edu/china/

    ↩

  14. Thompson. B. The Gardener's Assistant. Blackie and Son. 1878-00-00

    ↩

  15. Ohwi. G. Flora of Japan. (English translation) Smithsonian Institution 1965-00-00

    ↩

  16. Crawford, Matin Creating a Forest Garden: Working with nature to grow edible crops Green Books ISBN 978-1-900322-62-1 (2010/01/01)

  17. Toensmeier, Eric. Perennial Vegetables. Chelsea Green ISBN 978-1-931498-40-1 (2007/01/01)

  18. Workman, Dion. [Falling.] Shikigami (2013/07/31)

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