Erect annual, 30-90 (-200) cm tall, branched, + sparsely hairy below, glabrous above, with simple hairs. Lower leaves distinctly stalked, lyrate-pinnati¬fid, 2-3-jugate; margin irregularly and coarsely dentate; middle leaves ± simple, oblong-ovate, dentate; upper leaves oblong-linear, acute, narrowed at the base into a short stalk, entire or subentire. Racemes 20-40-flowered, lax, increasing up to 30 cm in fruit. Flowers c. 7 mm across, golden yellow; pedicel 5-8 mm long, increasing up to 15 mm in fruit, glabrous, ascending. Sepals 4-6 mm long, 1-1.5 mm broad, oblong, subequal, apex rounded or obtuse, yellowish, glabrous. Petals 6-9 mm long, 2.5-3 mm broad, obovate, clawed, apex rounded. Stamens 4-6:5-8 mm long; anthers about 2 mm long, obtuse with apex often curved. Siliquae 25-50 mm long, 2-3 mm broad, linear, subtetragonous, suberect, + torulose, narrowed into a 5-10 mm long seedless beak, glabrous; valve with a prominent mid-rib, yello¬wish; style 1.5-2.5 mm long with a short stigma; septum white, membranous. Seeds 10-20 in each locule, c. 1 mm in diam., globose, reddish-brown.

Fl. Per.: March-May.

Type: Described from Asia.

Distribution: Probably wild in C. Asia (Asiatic origin) ; cultivated extensively and introduced in most parts of the world. Often found as an escape from cultivation.

Some authors recognize three varieties, glabrous, sparsely hispid, and hispid (Blatter in J. Bombay Nat. Hist. Soc., 34 (3) : 299, 1930) which are of doubtful taxonomic value, as it is impossible to draw a definite line between these indumen¬tum characters and their constancy. Much honey is collected by insects from its flowers and seeds are oil producing (both fatty oil and volatile “mustard” oil.