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Dioscorea balcanica, habit of a flowering plant

Dioscorea balcanica , habit of a flowering plant

Department : Vascular plants (tracheophyta)
Subdivision : Seed plants (Spermatophytina)
Class : Bedecktsamer (Magnoliopsida)
Order : Yams (Dioscoreales)
Family : Yams
Scientific name

The yam family (Dioscoreaceae), also called yam family , yam family or wormwood family , are a family in the order of the yam-like (Dioscoreales).

The family includes three genera with around 600 to 870 species . Their types are mainly found in warm to tropical climates. In Central Europe, there is only one type of yam plant native, the Schmerwurz ( Dioscorea communis ). Some species are starch-producing food crops and the ingredients of some species are known for their medicinal properties .


Illustration of the common wormwood ( Dioscorea communis )

Habit and leaves

These plant species grow as perennial herbaceous climbing plants or woody lianas , rarely shrubs . They mostly form rhizomes or tubers as storage organs .

Common carpenter's leaves ( Dioscorea communis )

The leaves are seldom opposite, mostly alternate and arranged helically on the stem axis . The leaves are often divided into a petiole and a leaf blade. This is only seldom the case with monocot plants , but is found e.g. B. also with the jacks . Extra-floral nectaries are often found on the leaves, which are often large . The leaf blades are simple or compound; the leaf veins are arched and palmatized and the leaf margin is smooth.

Inflorescences and flowers

The flowers are arranged in differently structured inflorescences . There are separate sexes, mostly dioecious ( diocesan ), but there are also monoecious ( monoecious ) taxa .

The mostly unisexual, in Stenomeris hermaphroditic flowers are threefold and radial symmetry . The bracts are designed the same and have six tepals . Nectaries are present in the flowers. In the male flowers there are usually two circles with three stamens each. Either all of the stamens are fertile or those of a circle are converted to staminodes. The three pistils have become an under constant (syncarp) ovary grown.
The flower formula is:


Different fruits are formed. They are mostly triangular, loculicidal capsule fruits , less often fleshy berries or single-seeded samara .

Harvested yams

Ingredients and usage

Yams contain flavonols and calcium oxalate . In parts of the yam family, steroid saponins (e.g. diosgenin ) can often be found; they can be used as a starting material for the semi-synthetic production of some hormones .

Many species are grown as useful plants in the tropics ( yams ). For example, Dioscorea batatas is planted in East Asia . Their underground tubers are edible and an important source of starch in the tropics .

Some species ( Dioscorea elephantipes (L'Hér.) Engl. , Dioscorea mexicana Scheidw. , Dioscorea sylvatica Eckl. , Dioscorea macrostachya Bentham (Syn .: Testudinaria macrostachya (Bentham) Rowley )) are used as "succulent" ornamental plants ; however, they are not succulent, but have interestingly shaped tubers.


The family name was first published in 1810 by Robert Brown in Prodromus Florae Novae Hollandiae , 294. The type genus is Dioscorea L. For a long time, only the species that are now included in the genus Dioscorea belonged to this family; the species of some former genera have been incorporated into the Dioscorea since 2000 . Some authors also include the species of the genus Tacca , which can represent a separate family Taccaceae , here. The genera of the previously independent families Avetraceae Takht. , Stenomeridaceae J.Agardh , Tamaceae Bercht. & J. Presl , Tamnaceae J. Kickx f. and Trichopodaceae Hutch. are now part of the Dioscoreaceae R.Br. assigned.

Here are the three genera of the yams (without Tacca ):

  • Yam ( Dioscorea L. , Syn. : Borderea Miègev. , Botryosicyos Hochst. , Elephantodon Salisb. , Epipetrum Phil. , Hamatris Salisb. , Helmia Kunth , Higinbothamia Uline , Hyperocarpa (Uline) GMBarroso , Merione Salisb. , Nanarepenta Matuda , Oncorhiza Pers . , Oncus Lour. , polynomials Salisb. , Rajania L. , Rhizemys Raf. , Ricophora Mill. , Sismondaea Delponte , Strophis Salisb. , tamus L. , Tamnus Mill. , Testudinaria Salisb. ex Burch. , Ubium J.F.Gmel. ): It is pantropically distributed with around 600 (350 to 800) species today.
  • Stenomeris planch . (Syn .: Halloschulzia Kuntze ): The only two types are common in western and central Malesia :
  • Trichopus Gaertn. (Syn .: Avetra H.Perrier ): It contains two types:



Individual evidence

  1. a b c d e f g h Rafaël Govaerts (Ed.): Dioscoreaceae. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved June 24, 2018.

Web links

Commons : Yams (Dioscoreaceae)  - Collection of images, videos, and audio files