Dioscorea

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Dioscorea
Dioscorea balcanica BotGardBln310505.jpg
Dioscorea balcanica
Scientific classification e
Kingdom: Plantae
Clade: Angiosperms
Clade: Monocots
Order: Dioscoreales
Family: Dioscoreaceae
Genus: Dioscorea
L.
Sections
  • Enantiophyllum
Synonyms[1]
  • Tamus L.
  • Ricophora Mill.
  • Tamnus Mill.
  • Oncus Lour.
  • Ubium J.F.Gmel.
  • Oncorhiza Pers.
  • Testudinaria Salisb. ex Burch.
  • Rhizemys Raf.
  • Botryosicyos Hochst.
  • Helmia Kunth
  • Sismondaea Delponte
  • Epipetrum Phil.
  • Borderea Miégev.
  • Elephantodon Salisb.
  • Hamatris Salisb.
  • Merione Salisb.
  • Polynome Salisb.
  • Strophis Salisb.
  • Higinbothamia Uline
  • Nanarepenta Matuda
  • Hyperocarpa (Uline) G.M.Barroso, E.F.Guim. & Sucre

Dioscorea is a genus of over 600 species of flowering plants in the family Dioscoreaceae, native throughout the tropical and warm temperate regions of the world. The vast majority of the species are tropical, with only a few species extending into temperate climates.[1][2][3][4] It is named after the ancient Greek physician and botanist Dioscorides.

Description[edit]

They are tuberous herbaceous perennial lianas, growing to 2–12 metres (6.6–39.4 ft) or more tall. The leaves are spirally arranged, mostly broad heart-shaped. The flowers are individually inconspicuous, greenish-yellow, with six petals; they are mostly dioecious, with separate male and female plants, though a few species are monoecious, with male and female flowers on the same plant. The fruit is a capsule in most species, a soft berry in a few species.[5][6]

Cultivation and uses[edit]

Several species, known as yams, are important agricultural crops in tropical regions, grown for their large tubers. Many of these are toxic when fresh, but can be detoxified and eaten, and are particularly important in parts of Africa, Asia, and Oceania (see yam article).

One class of toxins found in many species is steroidal saponins, which can be converted through a series of chemical reactions into steroid hormones for use in medicine and as contraceptives.

The 1889 book 'The Useful Native Plants of Australia records that Dioscorea hastifolia is "One of the hardiest of the yams. The tubers are largely consumed by the local aborigines for food. (Mueller)."[7]

Accepted species (613), subspecies, and varieties[edit]

The genus includes the following species and subspecies:[citation needed]

The closely related genus Tamus is included in Dioscorea by some sources,[9] but is maintained as distinct by others.[10] For Dioscorea communis (L.) Caddick & Wilkin, see Tamus communis.

See also[edit]

References[edit]

  1. ^ a b "World Checklist of Selected Plant Families: Royal Botanic Gardens, Kew". apps.kew.org. Retrieved 2017-01-23.
  2. ^ Govaerts, R., Wilkin, P. & Saunders, R.M.K. (2007). World Checklist of Dioscoreales. Yams and their allies: 1-65. The Board of Trustees of the Royal Botanic Gardens, Kew.
  3. ^ Wilkin, P. & Thapyai, C. (2009). Flora of Thailand 10(1): 1-140. The Forest Herbarium, National Park, Wildlife and Plant Conservation Department, Bangkok.
  4. ^ "Dioscorea communis [Tamaro]". luirig.altervista.org (in Italian). Retrieved 2017-01-23.
  5. ^ "Dioscorea in Flora of North America @ efloras.org". www.efloras.org. Retrieved 2017-01-23.
  6. ^ "Dioscorea in Flora of China @ efloras.org". www.efloras.org. Retrieved 2017-01-23.
  7. ^ J. H. Maiden (1889). The useful native plants of Australia : Including Tasmania. Turner and Henderson, Sydney.
  8. ^ Wilkin, Paul; Annette Hladik; Odile Weber; Claude Marcel Hladik; Vololoniana Jeannoda (September 2009). "Dioscorea orangeana (Dioscoreaceae), a new and threatened species of edible yam from northern Madagascar". Kew Bulletin. 64 (3): 461–468. doi:10.1007/s12225-009-9126-2. ISSN 1874-933X. Retrieved 10 June 2010.
  9. ^ World Checklist of Selected Plant Families, The Board of Trustees of the Royal Botanic Gardens, Kew, retrieved 2011-05-28, search for "Tamus"
  10. ^ Stace, Clive (2010), New Flora of the British Isles (3rd ed.), Cambridge, UK: Cambridge University Press, ISBN 978-0-521-70772-5, p. 854

Bibliography[edit]