Sisymbrium nigrum (L.) Prantl
Annual, 30-100 cm tall, erect, usually bristly hairy below, glabrous and glaucous above, branched. Lower leaves deeply pinnatifid or pinnatisect, 6-25 cm long, 3-12 cm broad, 1-3-jugate with a large ovate terminal lobe and much smaller ovate-oblong lateral lobes, sinuate dentate, stalked; upper leaves becoming much smaller, narrowly elliptic or lanceolate, short stalked. Racemes 40-60-flowered, increasing up to 30 cm in fruit. Flowers 5-8 mm across, bright yellow; pedicel 2-3 mm long, about as long as the sepals in fruit otherwise shorter, ± appressed to the axis, not thickened. Sepals 3-5 mm long, 1-1.2 mm broad, oblong, obtuse, yellowish, glabrous. Petals 7-9 mm long, 3-4 mm broad, obovate, clawed. Stamens c. 4: 5 mm. long; anthers c. 1 mm long. Siliquae 10-20 mm long, 1.5-2 mm broad, including 1.5-3 mm long beak (with c. 1 mm long style and capitate stigma), oblong, subquadrangular; valve with a strong mid-vein, glabrous, subtorulose; septum not veined, membranous; seeds 3-6 in each locule, c. 1 mm in diam., dark-brown (blackish), not mucilaginous when wet; coarsely finely reticulated.
Fl. Per. : March-May.
Type: Described from Europe.
Distribution: Europe, W. Asia and N. Africa. Widely introduced and cultivated for volatile oil and mustard powder from its seeds.
Very distinct from other Brassicas by its short appressed pods with hardly any beak in the true sense.
Black mustard is not much cultivated in the area. Its seeds have medicinal use as poultice and an oil is extracted from it.