CLASS XV. ORDER 11.] SINAPlS. 917 



1. S. arven'sis, Linn. (Fig. 1059.) Wild Mustard, Charlock. 

 Siliqua cylindrical, turgid, knotty; valves v^ilh three prominent ribs, 

 longer than the two edged beak; calyx spreading horizontally ; leaves 

 rough, the radical ones sub-lyrale and toothed, the upper sessile, ovate. 



English Botany, t. 1748 — English Flora, vol. iii. p. 221. — Hooker, 

 British Flora, ed. 4. vol. i. p. 256. — Lindley, Synopsis, p. 33. 



Root tapering. Stem erect, about two feet high, round, striated, 

 rough, with reflexed bristles, branched, mostly tinged with purple. 

 Leaves dark green, rough, with rigid bristles, the lower ones petiolated, 

 somewhat lyrate, the lobes toothed unequally, the upper ones ovate, 

 sessile, unequally toothed, sometimes lobed. Injiorescence terminal 

 sub-corymbose clusters of bright yellow flowers, becoming much 

 elongated after flowering. Calyx of four oblong horizontally spread- 

 ing pieces, of a pale yellow colour. Petals four, obovate or heart- 

 shaped, tapering into a claw. Stamens with awl-shaped ^/awew^^, the 

 anthers ovate, two celled. Fruit a cylindrical knotty siliqua, rough, 

 with short bristles, the valves each with three prominent ribs, the beak 

 compressed, furrowed, about half as long as the valves. Seeds globose, 

 brown. 



Habitat. — Corn fields and cultivated or waste places ; frequent. 



Annual ; flowering in May and June. 



This is an extremely common plant in the light sandy soils of some 

 parts of the country, and a very troublesome weed ; for oft 

 *' O'er the young corn the Charlock throws a shade, 

 And clasping Tares cling round the sickly blade." 



The seeds possess acrid pungent properties, but in a less proportion 

 than those of the following species, and of a less agreeable flavour, 

 and consequently they are not cultivated for use, though often mixed 

 with the others. 



2. S. al'ba, Linn. (Fig. 1060.) White Mustard. Siliqua cylin- 

 drical, turgid, the valves with five prominent ribs, shorter than the two 

 edged beak; calyx spreading horizontally; leaves pinnatifid, with 

 broadish unequally toothed lobes. 



English Botany, t. 1677.— English Flora, vol. iii. p. 222.— Hooker, 

 British Flora, ed. 4. vol. i. p. 256.— Lindley, Synopsis, p. 33. 



Root tapering, small. Stem erect, from one to two feet] high, 

 striated, branched and leafy, rough, with reflexed hairs. Leaves 

 rough, a dark bright green, all pinnatifid, with broad ovate lobes, 

 unequally toothed or sinuated, the terminal leaflet mostly three lobed. 

 Inflorescence terminal sub-corymbose bright yellow flowers, becoming 

 much elongated racemes when in seed. Calyx of four linear horizon- 

 tally spreading pale yellowish green pieces. Petals of four obovate 

 spreading pieces, tapering into a claw. Stamens with slender Jila- 

 ments. Fruit a cylindrical rough siliquat the valves short, tumid, 

 striated, with five prominent ribs, terminated by a compressed tapering 



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