Dioscorea alata

Non-woody vine, twining (toward the right), glabrous, attaining 10Ð15 m in length. Root system fibrous, shallow, mostly confined to the top 1 m of the soil. Tubers usually single, varying in size and shape, often very large;cylindrical or clavate in shape (often found as deep as 1.5 m) or globose, stout and short, pyriform, often variously lobed or fingered and fasciated or curved;skin brown to black;flesh white, cream or purplish (superficially or throughout). Stems are quadrangular, with 4 longitudinal winged, undulate, green or reddish projections;mature stems (at the base) cylindrical and spiny. Leaves are mostly opposite, sometimes alternate on branches of rapid growth, coriaceous, broadly ovate, 5- to 7-veined, 10Ð30 x 5Ð18 cm, the apex acute or acuminate, sometimes reflexed, the base cordiform;upper surface dark green, shiny, with the venation sunken;lower surface pale green, dull, with prominent venation;petioles 4Ð12 cm long, 4-winged, forming an auriculate sheath at the base, with a pair of pseudostipules that clasp the stem;bulbils elongate, pendulous, attaining 15 cm long, produced when the leaves begin to wither. Inflorescences are axillary, unisexual, pendulous. Staminate inflorescences are paniculate, 5Ð15 cm long, with numerous lateral and flexuous spikes that contain numerous male flowers. Pistillate inflorescences are racemose, with few flowers. Perianth 1Ð1.5 mm long in staminate flowers;2Ð2.8 mm long in pistillate flowers. Fruit a 3-locular capsule, 2Ð3 cm wide, each locule flattened like a wing, with two seeds inside (Acevedo-Rodr’guez, 2005). Seed orbicular, winged all round.