40 



FIG. 15. 



WILD MUSTARD, CHARLOCK, OR HERRICK. 

 Brassica sinapistrum (L). 



Among the worst weeds in Ontario is the Wild Mustard, an annual, 

 naturalised from Europe, with fibrous roots and erect habit of growth. 

 The stem is rough, with stiff hairs somewhat scattered over the surface. 

 The branches arise from the upper part of the stem and bear oblong 

 leaves ; and the lower leaves have one terminal large lobe and several 

 smaller lateral ones (lyre-shaped). The flowers are yellow, showy, and 

 about f in. broad, with stout flower stalks, which are more noticeable 

 when the plant is in fruit. The pods, which appear on the lower part of 

 the stem whilst the top is still in flower, are from 1 to 2 inches long, and 

 are either spreading or ascending. 



The shape of the pod is characteristic ; it is constricted between 

 the seeds, thus giving the appearance of a rounded enlargement where 

 each seed is borne. This appearance is termed " knotted." The 

 pod terminates in a two-edged beak, and the two valves of the pod are 

 strongly veined or ribbed. 



The seed (See Fig. 15) is black, J in. in diameter, perfectly spheri- 

 cal, and very much like rape or turnip seed ; and it retains its vitality 

 for a long time when buried in the soil. An average plant produces 

 15,000 seeds. 



Time of flowering, June- September. Time of seeding, July-Septem- 

 ber. 



Dispersal by birds and implements, but chiefly as an impurity in 

 seed. 



Eradication. Owing to the great vitality of the seed, Mustard is a 

 very hard weed to eradicate. The seeds, once in the ground, live for 

 years and continue to germinate as they are brought near the surface. 

 Hence it takes patience, a great deal of labor, and a long time to get rid 

 of the weed, when it once gets possession of the land. When present 

 only in small amounts, hand-pulling is the best method, provided the 

 pulling is done before seeds have formed ; arid as persons pulling in a 

 hurry cannot wait to examine for seed, it is best to put the weeds, as 

 they are pulled, in bundles where they can be burned when dry. 



When fields are overrun with the weed, it is best to proceed as fol- 

 lows : Harrow stubble-ground early after harvest, or gang-plow and 

 harrow. As soon as the seeds have had time to sprout, cultivate thor- 

 oughly ; repeat cultivation at intervals ; and rib up with a double mould- 

 board plow the last thing in the fall. Put in a hoed crop, either roots or 

 corn, the following spring,and cultivate it thoroughly throughout the grow- 

 ing season. Cultivate and harrow well two or three times after roots or 

 corn, having first run the plow along each row of corn roots to cut the 

 roots and turn them up ; and rib up before the frost. (If the plow is 



