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common name for some members of the Dioscoreaceae, a family of tropical and subtropical climbing herbs or shrubs with starchy rhizomes often cultivated for food. The largest genus, Dioscorea, is commercially important in East Asia and in tropical America. The thick rhizomes, often weighing 30 lb (13.6 kg) or more, are used for human consumption and for feeding livestock. A number of species of Dioscorea are cultivated for extraction of diosgenin, a female hormone precursor used in the manufacture of the contraceptive pill. In the United States, cultivation of yams for food is restricted to the South, but the wild yam (sometimes used medicinally) is indigenous farther north, and another species, the cinnamon vine, is cultivated as a decorative plant. The sweet potatosweet potato,
trailing perennial plant (Ipomoea batatas) of the family Convolvulaceae (morning glory family), native to the New World tropics. Cultivated from ancient times by the Aztecs for its edible tubers, it was introduced into Europe in the 16th cent.
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, which belongs to the morning glory family, is sometimes erroneously called yam. The S African elephant's-foot (Testudinaria elephantipes), also called Hottentot bread and tortoise plant, is sometimes grown in greenhouses; its large rootstock was formerly eaten by the natives. Yams are classified in the division MagnoliophytaMagnoliophyta
, division of the plant kingdom consisting of those organisms commonly called the flowering plants, or angiosperms. The angiosperms have leaves, stems, and roots, and vascular, or conducting, tissue (xylem and phloem).
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, class Liliopsida, order Liliales, family Dioscoreaceae.



any one of more than 30 plant species of the genus Dioscorea of the family Dioscoreaceae. Yams are cultivated for their tubers in the tropics and subtropics. The tubers are different morphologically (thickening of the hypocotyl, internodes, or rhizomes). In some species, they reach a length of 1.5 m and a weight of 50 kg. The tubers are used as food in a way similar to potatoes. The poisonous substances found in the tubers of some species are usually destroyed during boiling or baking. The most important species are the Chinese yam (D. batatas), winged yam (D. alata), D. esculenta, and the air potato (D. bulbifera).


Ipat’ev, A. N. Ovoshchnye rasteniia zemnogo shara. Minsk, 1966.
Siniagin, I. I. Tropicheskoe zemledelie. Moscow, 1968.
Uphof, J. C. T. Dictionary of Economic Plants, 2nd ed. Lehre, 1968.

What does it mean when you dream about a yam?

Yams are usually associated with the holiday season. The dreamer’s associations with this symbol may be rooted in memories of family celebrations. As a plant that grows under the ground, the yam is also a natural symbol of something deeply rooted in the unconscious mind.


A plant of the genus Dioscorea grown for its edible fleshy root.
An erroneous name for the Puerto Rico variety of sweet potato; the edible, starchy tuberous root of the plant.


1. any of various twining plants of the genus Dioscorea, of tropical and subtropical regions, cultivated for their edible tubers: family Dioscoreaceae
2. Southern US any of certain large varieties of sweet potato
3. a former Scot name for the (common) potato
References in periodicals archive ?
By the time we carry 40 wagons of yam to Lagos, Kano, Kaduna and other cities, there will be an influx of the commodity in the cities and that is food security and that will be good for all,' he said.
According to Yam, he has been "loyal" and "honest" to her that's why their relationship lasts.
Yam tuber productivities (Table 2) were higher in the pigeon pea treatment (33.
Get the YAM logo online and display it in all your school happenings.
Yam, for his part, expressed the hope that Iran and Mongolia would boost mutual cooperation in the agricultural and cattle-breeding fields given the two countries' infrastructures and capacities in both sectors.
Inside the greenhouse, you have an irrigation system and mist system and the yam plantlets or vine is suspended on a table with the mist continuously feeding the plant in a soil-free environment allowing seed yam tuber production.
According to the results of the SEM images (Table 1), both the nanofiber and yam diameters decreased by increasing the twist rate from 160 to 288 rpm.
Train and support yam farmers on good agricultural practices and buyers requirements;
Kate | and William with Tony Tan Keng Yam and his wife Mary
Earlier, African expatriates would buy a single tuber of yam from their colleagues and friends, who brought it from home, for up to QR60.
Sweet potatoes have either a lighter orange skin with a yellow, drier flesh (more like a white baking potato) or a darker orange skin (which leads to yam comparisons) with moist, sweeter flesh than the lighter-skinned kind.
The temporary prohibition is in effect for the next two weeks as the embassy will assess the security implications of the December 22 bomb attack on a public bus in Bat Yam.