An annual or biennial herb, cultivated as a vegetable, strange looking vegetable, with an enlarged bulb-like swelling (corm) that develops on the stem a few inches above the ground; the corm sprout long petioles (leaf stems) with leaves that resemble those of the cabbage; the whole plant is about 0.6 m tall. In its second growing season, it produces an inf;orescence. Flowers yellow. Fruit a sickle shaped pod. Seeds black.