B. monensis: biennial, or short-lived perennial; stem prostrate, glabrous, sometimes barely six inches high, the leaves mostly radical; leaves pinnatifid or pinnate, the lobes oblong with a few coarse teeth, upper ones more deeply divided, with narrower segments; flowers rather large, pale yellow; pods spreading 14 - 2 inches long, terminating in a thick beak, which is from 1/3-1/5 of the whole length, and contains 1-3 seeds. - Sandy western coasts. Fl. June to August.
Var. Cheiranthus: more luxuriant, the stem 1-3 feet high, erect, leafy, hairy at the base. - South Wales and the Channel Islands.
** Valves of the pod one-ribbed. † Upper leaves stem-clasping, not auricled.
B. oleracea: stock thick, almost woody, of 2-3 years' duration, branching into erect stems 1-2 feet high; leaves smooth, glaucous, the lower ones stalked, broad, sinuate, or lobed at the base, the upper oblong, clasping the stem by their broad base, but not auricled; flowers rather large, pale yellow; pod spreading, 1 1/2 inches or more in length. - Maritime cliffs, probably escaped from cultivation. Fl. June to August.
The cultivated forms of this species include the garden Cabbage, Cauliflower, Kale, etc.
†† Upper leaves stem-clasping, with auricles.
B. campestris: annual; stem 1-2 feet high, erect, simple, or scarcely branched; leaves green, slightly glaucous, pinnately divided, with a large terminal lobe, rough with stiff hairs, which are rarely wanting, upper ones narrow-oblong or lanceolate, stem-clasping, with rounded projecting auricles; flowers bright yellow; pods resembling those of the last. - Borders of fields and waste places, a frequent weed of cultivation. Fl. June, July.
The cultivated varieties include the Turnip (B. Napus), the Rape-seed or Colza (B. Rapa), etc.
(28) Sinapis. Mustard. * Pods spreading from the axis of the inflorescence.
S. alba: annual; stem 1-2 feet high, glabrous or with spreading hairs; leaves lyrate, i.e. pinnately lobed or divided, the terminal one largest, the lobes ovate or oblong, coarsely toothed; flowers rather large, yellow; pods spreading, knotty, hispid with stiff hairs, shorter than the sword-shaped beak. - Waste and cultivated places; often cultivated for salad. Fl. June.
S. arvensis: annual; stem 1-2 feet high, with a few spreading hairs; leaves rough, the lower ones with one large terminal oval-oblong, coarsely-toothed segment, and a few smaller ones, the upper often undivided; flowers yellow, rather large; pods spreading, about a third occupied by a stout awl-shaped beak, the valves glabrous, or rough with reflexed hairs. - Charlock. - A common weed of cultivation. Fl. June, July.
** Pods erect, oppressed to the axis of inflorescence.
S. nigra: annual, less hairy than the preceding; stem two feet high; leaves deeply divided, with one large terminal ovate or oblong lobe and a few small lateral ones, the upper often small and entire; flowers small, yellow; pods closely pressed against the axis of the long slender racemes, glabrous, with a small beak. - Waste and cultivated places. Fl. June, July.