48 FARM FRIENDS AND FARM FOES 



The Black Mustard is a much more prickly plant, having 

 pods that are more or less oblong, smooth, and four-angled. 

 A single plant of either of these Mustards may produce 

 from 10,000 to 1 5,000 seeds. This accounts for the enormous 

 numbers of them that often appear in neglected fields. 



In many parts of Canada and the United States, the 

 Tumbling Mustard or Tall Mustard has recently become 

 a troublesome pest. This species seems to have been in- 

 troduced with the soil carried as ballast by ships, and dumped 

 on the so-called ballast grounds at Philadelphia. It has 

 since been widely distributed by railroads, and is able to 

 develop under a great variety of climatic conditions. Like 

 the other Mustards, this is an annual. It branches freely, 

 and reaches a height of from two to four feet. The small 

 yellowish flowers are borne along the tips of the slender 

 branches, and are less conspicuous than those of the Char- 

 lock. The seed pods are very slender, and are commonly 

 two or three inches long. This species is closely related to 

 the more widely distributed Hedge Mustard, the pod of 

 which is much shorter and of larger diameter. 



In the case of all these Mustards, as with most annual 

 weeds, careful cultivation with a hoed crop for a series of 

 years is necessary for complete extermination in a field. The 

 seeds of many of the plants of the Mustard family retain 

 their vitality for several years, so that those which are 

 buried deep in plowing, are likely to be brought to the 

 surface long after they matured, and find favorable condi- 

 tions for growth. It is especially important that grain 

 used for sowing be free from the seeds of any of these 

 plants. 



Numerous experiments have shown that young mustard 

 plants may be killed in grain fields without serious injury 

 to the grain crop by spraying with a solution of one part 



