WEEDS: INJURY TO CROPS AND NATURE OF 5 



broken them open, the weeds cause the greatest damage 

 by robbing the soil of the necessary moisture ; the grain 

 must, therefore, be shriveled in maturing." 



Root rot of cotton is abundant on many plants, but es- 

 pecially so on members of the mallow family, as sida and 

 shoofly. In this way this fungus is transmitted to cotton, 

 sweet potato and the apple tree. 



It is not unusual for owners of elevators to dock wheat 

 containing a great deal of any weed seed proving difficult 

 of removal, although the wheat itself might be graded 

 No. i. The seed of kinghead cannot be taken out by the 

 proper elevator machinery, hence the elevator men at 

 Duluth decided that after August I, 1910, they would 

 dock wheat that contained a great deal of kinghead. In 

 the grain-growing states of the Dakotas and Minnesota, 

 there is considerable dockage on account of weed seeds 

 and the same is also true of the Canadian Northwest 

 provinces. The loss to the farmers must amount to mil- 

 lions of dollars a year. 



Certain weeds are injurious because when they be- 

 come mixed with small grain, they must be removed be- 

 fore it can be sold as " A " wheat or oats, although all 

 other conditions may be fulfilled. Where there is much 

 mustard in oats, the grain will not bring so good a price 

 as clean oats do, and the same may be said of wheat 

 containing cockle, vetch, cow herb, garlic, sweet clover, 

 etc. 



Some Weeds Are Useful. Weeds may in some cases 

 serve some useful purpose. Digitalis is obtained from 

 foxglove ; hyoscyamine from black henbane ; daturin 

 from Jimson weed. Many weeds, like tansy and hemp, 

 have medicinal properties. Others serve culinary pur- 

 poses, as when the roots of chicory are used as a substi- 

 tute for coffee. Lamb's quarter, dandelion and the 

 young shoots of pokeweed are used as spring greens. 

 The roots of tan weed or shoestring (Muhlenberg's 



