Dioscorea alata, known as purple yam and many other names, is a species of yam, a tuberous root vegetable, that is bright lavender in color. It is sometimes confused with taro and the Okinawa sweet potato (Ipomoea batatas cv. Ayamurasaki). With its origins in the Asian tropics, D. alata has been known to humans since ancient times.
Because it has become naturalized throughout tropical South America, Africa, Australia, the US southeast, D. alata has many different common names from these regions. In English alone, aside from purple yam, other common names include greater yam, Guyana arrowroot, ten-months yam, water yam, white yam, winged yam, or simply yam. In other cultures and languages it is known variously as ratalu or violet yam in India, rasa valli kilangu in Tamil, kondfal (कोंदफळ) in Marathi, kachil (കാച്ചില്) in Malayalam, and khoai mỡ in Vietnam and for the Igbo people of Southern Nigeria, yam is called ji, and purple yam is known as ji abana.
*qube / *ʔube can be reconstructed as the Proto-Malayo-Polynesian word for D. alata, and words descended from it are found throughout the geographic range of this widespread language family, though in some daughter languages they are generalized or transferred to other root crops. Examples include Tagalog ube or ubi, Indonesian and Malay ubi**, Malagasy ovy**, Fijian uvi, Tongan ʻufi, Samoan ufi**, as well as Māori and Hawaiian uhi. D. alata was one of the canoe plants that the Polynesians brought with them when they settled new islands.
** Not specific to D.alata
Purple yam is used in a variety of desserts, as well as a flavor for ice cream, milk, Swiss rolls, tarts, cookies, cakes, and other pastries. In the Philippines, it is known as ube and is eaten as a sweetened jam called ube halayá, a popular ingredient in the iced dessert called halo-halo. In Maharashtra, the stir-fried chips are eaten during religious fasting. Purple yam is also an essential ingredient in Undhiyu.
D. alata is sometimes grown in gardens for its ornamental value.
Dioscorea alata is an introduced plant persisting in the wild in the United States in Louisiana, Georgia, Florida, Puerto Rico, and the U.S. Virgin Islands. It is also an invasive species, at least in Florida.
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- Dioscorea alata was first described and published in Species Plantarum 2: 1033. 1753. "Name - Dioscorea alata L.". Tropicos. Saint Louis, Missouri: Missouri Botanical Garden. Retrieved May 26, 2011.
- "The Plant List: A Working List of All Plant Species".
- GRIN (May 9, 2011). "Dioscorea alata information from NPGS/GRIN". Taxonomy for Plants. National Germplasm Resources Laboratory, Beltsville, Maryland: USDA, ARS, National Genetic Resources Program. Retrieved May 26, 2011.
- Blust, Robert (2010). "Austronesian Comparative Dictionary, web edition: *qubi yam: Dioscorea alata Linn.". In Trussel, Stephen. http://www.trussel2.com/ACD. Retrieved 23 August 2013.
- James A. Duke. "Dioscorea alata (DIOSCOREACEAE)". Dr. Duke's Phytochemical and Ethnobotanical Databases. Retrieved May 26, 2011.
- "Profile for Dioscorea alata (water yam)". PLANTS Database. USDA, NRCS. Retrieved May 26, 2011.