Yam and its Descriptions

Yam is the common name for some plant species in the genus Dioscorea (Diosaceae) that form edible tubers.The tubers of some other species of the genus, such as D.communis, are poisonous.Yams are herbaceous perennial vines grown for their starchy tubers in many temperate and tropical regions, especially in West Africa, South America and the Caribbean, Asia and Oceania.The tuber itself, also known as "yam," comes in many forms due to the large number of cultivars and related species.Yams have been domesticated independently on three different continents: Africa (D.rotundata), Asia (D.alata), and the Americas (D.trifida).

Etymology 

The name "yam" appears to be derived from the Portuguese inhame or the Canarian Spanish ñame, which in trade is derived from West African languages.In Portuguese, however, the name usually refers to the taro plant (Colocasia esculenta) from the genus Taro, not to the yam plant.The main derived borrowed verb means "to eat".True yams have different common names in several world regions.Other (unrelated) root vegetables are sometimes called "yams" in some places, including:

• In the United States, sweet potatoes (Ipomoea batatas), especially those with orange flesh, are often called "yams".

• In Australia, tubers of Microseris lanceolata or yam daisy are a staple food of Aboriginal Australians in certain regions.

• In New Zealand, oca (Oxalis tuberosa) is often called "yam".

• In Malaysia and Singapore, taro (Colocasia esculenta) is known as "yam".

• Amorphophallus konjac, known as "elephant's foot", is grown in Africa, South and Southeast Asia, and the tropical islands of the Pacific Ocean.

Describe

Yams, a monocotyledonous plant related to lilies and grasses, are vigorous herbaceous, perennial vines that grow from tubers.They are native to Africa, Asia, and the Americas. About 870 species of yams are known,some of which are widely cultivated for their edible tubers, but others are poisonous.Some yams are also invasive plants, often considered "noxious weeds" outside of cultivated land.95% of these crops are produced in Africa.Yam plants can reach lengths of up to 15 meters (49 feet) and heights of 7.6 to 15.2 centimeters (3 to 6 inches).Tubers can grow into the soil to a depth of 1.5 m (4 ft 11 in).Plants disperse by seeds.Edible tubers have rough skins that are difficult to peel, but are easily softened by cooking.The color of the skin varies from dark brown to light pink.The bulk or flesh of the vegetable consists of a softer substance that can vary in color from the white or yellow of a ripe yam to purple or pink.