Brassica nigra Illustration Credit: Shaukat & Azmat

Annual, biennial or perennial herbs, glabrous or hairy with simple, often setaceous hairs; roots slender or tuberous. Leaves alternate, lower rarely rosulate, lyrate, cuneate or amplexicaul. Racemes usually short and corymbose. Flowers mediocre, usually yellow, pedicellate, regular; pedicels increasing in length in fruit, often slightly thickened and spreading. Sepals sub-equal; outer oblong obtuse; inner ovate, sub-obtuse, saccate at the base. Stamens 6; filaments linear. Nectar glands often green in colour; laterals abruptly prismatic, often small; middle subglobose, oblong, filiform, sometimes large, up to 0.7 mm long. Gynop¬hore present or absent in fruit. Ovary cylindrical, 5-45 ovuled. Siliquae linear or oblong, cylindrical, rarely sub-compressed, often somewhat torulose; beak usually conical, rarely cylindrical or filiform, 0-3 seeded; valves with a prominent mid-vein; style with a prominent capitate sub-bilobed stigma; septum complete, hyaline, often somewhat thickened between the seeds; seeds uniseriate, globose or rarely ovoid, brown, finely alveolate; cotyledons conduplicate (longitudinally folded).

About 40 species mostly in the Mediterranean region; only 7 species are found in Pakistan, and of these only 2 are wild and the rest are known from cultivation only.

An important genus, including many vegetables and oil seed plants, taoxno¬mically very difficult because of the multitude of closely related races (Clapham et al, Fl. Brit. Isles, 147. 1952). Hence no attempt has been made here to mention all the infra specific categories except a few which are common.