Dioscorea

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Dioscorea
Dioscorea balcanica BotGardBln310505.jpg
Dioscorea balcanica
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Dioscoreales
Family: Dioscoreaceae
Genus: Dioscorea
L.
Sections
  • Botryosicyos
  • Combilium
  • Enantiophyllum
  • Lasiophyton
  • Macroura
    • Macrourae
  • Macrogynodium
  • Opsophyton
    • Euopsophyton
  • Shannicorea
  • Stenophora

(Not all are supported by molecular analyses. [1] See tropicos query cited for more. [2] )

Contents

Synonyms [3]
  • TamusL.
  • RicophoraMill.
  • TamnusMill.
  • OncusLour.
  • UbiumJ.F.Gmel.
  • OncorhizaPers.
  • TestudinariaSalisb. ex Burch.
  • RhizemysRaf.
  • BotryosicyosHochst.
  • HelmiaKunth
  • SismondaeaDelponte
  • EpipetrumPhil.
  • BordereaMiégev.
  • ElephantodonSalisb.
  • HamatrisSalisb.
  • MerioneSalisb.
  • PolynomeSalisb.
  • StrophisSalisb.
  • HiginbothamiaUline
  • NanarepentaMatuda
  • 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. [3] [4] [5] [6] It was named by the monk Charles Plumier after the ancient Greek physician and botanist Dioscorides.

Description

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. [7] [8]

Most Dioscorea species that have been examined possess extrafloral nectaries at the petiole or leaf underside. [9]

Cultivation and uses

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.

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)." [10]

Accepted species (613), subspecies, and varieties

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

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

The closely related genus Tamus is included in Dioscorea by some sources, [12] but is maintained as distinct by others. [13] For Dioscorea communis (L.) Caddick & Wilkin, see Tamus communis .

See also

References

  1. ↑ Couto, Ricardo S; Martins, Aline C; Bolson, Mônica; Lopes, Rosana C; Smidt, Eric C; Braga, João Marcelo A (28 September 2018). "Time calibrated tree of Dioscorea (Dioscoreaceae) indicates four origins of yams in the Neotropics since the Eocene". Botanical Journal of the Linnean Society. 188 (2): 144–160. doi: 10.1093/botlinnean/boy052 .
  2. ↑ "Name - Dioscorea L. (Subgeneric subordinate taxa)". legacy.tropicos.org.
  3. 1 2 "World Checklist of Selected Plant Families: Royal Botanic Gardens, Kew". apps.kew.org. Retrieved 2017-01-23.
  4. ↑ 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.
  5. ↑ Wilkin, P. & Thapyai, C. (2009). Flora of Thailand 10(1): 1-140. The Forest Herbarium, National Park, Wildlife and Plant Conservation Department, Bangkok.
  6. ↑ "Dioscorea communis [Tamaro]". luirig.altervista.org (in Italian). Retrieved 2017-01-23.
  7. ↑ "Dioscorea in Flora of North America @ efloras.org". www.efloras.org. Retrieved 2017-01-23.
  8. ↑ "Dioscorea in Flora of China @ efloras.org". www.efloras.org. Retrieved 2017-01-23.
  9. ↑ Weber, Marjorie G.; Keeler, Kathleen H. (2012-10-18). "The phylogenetic distribution of extrafloral nectaries in plants". Annals of Botany. 111 (6): 1251–1261. doi:10.1093/aob/mcs225. eISSN   1095-8290. PMC   3662505 . PMID   23087129.
  10. ↑ J. H. Maiden (1889). The useful native plants of Australia : Including Tasmania. Turner and Henderson, Sydney.
  11. ↑ 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" (PDF). Kew Bulletin. 64 (3): 461–468. Bibcode:2009KewBu..64..461W. doi:10.1007/s12225-009-9126-2. ISSN   1874-933X. S2CID   43183514.
  12. ↑ World Checklist of Selected Plant Families, The Board of Trustees of the Royal Botanic Gardens, Kew , retrieved 2011-05-28, search for "Tamus"
  13. ↑ 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

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