CRUCIFERAE (MUSTARD FAMILY) 187 
As a weed, this plant is usually the sur- 
vival of dormant seeds from former culti- 
vation, or an escape, though its seeds are 
occasionally found with those of other 
plants. 
Stems one to two feet high, branching, 
covered with stiff, spreading hairs. Lower 
leaves with slender petioles, deeply pin- 
natifid, the terminal lobe very large, the 
lateral lobes small and narrow, all toothed 
and rough-hairy ; upper leaves less divided, 
with shorter petioles or the topmost ones 
sessile. Flowers yellow, more than a half- 
inch broad, the sepals spreading and much 
shorter than the petals. Siliques round 
and very bristly, the beak often longer 
than the part containing the seeds. Seeds 
light yellow, smooth, larger than those of 
Black Mustard, milder in flavor. (Fig. 
130.) 
Means of control the same as for Char- 
lock and Black Mustard. 
BLACK MUSTARD 
Brédssica nigra, Koch. 
(Sindpis nigra, L.) 
Fie. 130. — White Mus- 
tard (Brassica alba). X 3. 
Introduced. Annual or biennial. Propagates by seeds. 
Time of bloom: June to September. 
Seed-time: July to November. 
Range: In most parts of the American Continent except the far 
North; most abundant on the Pacific Coast. 
Habitat: Fields and waste places. 
Mustard seeds, both the Black and the White, are used in making 
a popular condiment, also in medicine, and to express a fine, clear 
oil which has little or none of the sharp flavor of Mustard. The 
United States imports these seeds to the amount of over five million 
pounds annually, at a cost of three to six cents a pound. 
