[Boniatos (Caribbean); Talbos ng kamote (Philippines); Rau Lang (Viet); Di gua ye (Taiwan); Hong shu ye, Fan shu ye (China); Matembele (Congo); Ipomoea batatas of family Convolvulaceae]
What is sold as "Yam Leaves" in the markets is invariably Sweet Potato Leaves, because many real Yams have somewhat toxic leaves. Sweet Potato leaves are a popular green in much of the world, and they can be used as a substitute for the closely related Water Spinach, which is illegal in much of North America, but the texture of the stems will be different.
Sweet Potatoes originated in the Americas, but are now grown worldwide. They are easy to grow in tropical, subtropical, and warmer temperate regions, with good yield, and are a major crop. Even in many growing regions it is not commonly known that the leaves are edible and nutritious.
More on Morning Glories & Yams
Korea:, only peeled leaf stems are used (fresh or dried) and the leaves are discarded (see Sweet Potato Stems page). Peeling leaf stems is very tedious.
Philippines and the rest of Southeast Asia: the leaves are used whole with leaf stems left on. Salads, soups, and stir fries are popular.
China: for soups, the stems are chopped fairly fine and the leaves less fine. Leaves are used whole and stem-on in stir fries.
India: the leaves and leaf stems are are chopped small for Parippu Kootu and fine for Raita.
West, East, and Central Africa: leaves are used without stems, and generally chopped medium or small. Stews are popular, served beside a paste made from various root vegetables - rice too, but it is expensive.
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