Brassica alba (L.) Rabenh.
Annual, up to 75 (-100) cm tall, erect, branched, usually stiffly hairy with simple subdeflexed hairs. Lower leaves 5-15 cm long, 2-6 cm broad, ± hispid, lyrate, 2-3-jugate, stalked; the terminal lobe much larger than the laterals, usually 3-lobulate, coarsely and irregularly toothed; upper leaves shortly stalked, sub-equally lobulate, sinuate-dentate. Racemes many flowered, ebracteate, up to 30 cm long in fruit. Flowers c. 10 mm across, yellow; pedicel up to 14 mm long in fruit, spreading or subdeflexed. Sepals 4-5.5 mm long, 1-1.5 mm. broad, oblong, subspreading yellowish. Petals 7-12 mm long, 3.5-5 mm broad, obovate, clawed. Stamens 4-5: 5-7 mm long. Siliquae 20-40 mm long, 3-4 mm broad (including beak about as long or longer than the valves), sub-cylindrical, torulose, bristly hairy; beak ± compressed, sabre-shaped, often curved and 0-1-seeded; valve strongly 3. parallel veined; septum sub-membranous, thick, not veined; seeds 1-4 in each locule, globose, about 2 mm in diam., finely alveolate, pale brownish.
Fl. Per.: April June.
Type: Described from Europe: England, Belgium etc., Herb. Linn. no. 845/4 (LINN).
Distribution: Europe, N. Africa, S.W. Asia; widely introduced.
`White mustard' is occasionally cultivated as green fodder and its seed con¬tain about 35% oil.