WEEDS OF GRAIN AND FORAGE CROPS 49 



iron sulphate to four parts water by weight. The applica- 

 tion should be made on a fair day after the dew has evapo- 

 rated. 



Another member of the Mustar.d family, which is 

 troublesome in fields of winter grain, as well as in those of 

 flax, is the so-called False Flax. This is a pest from 

 Europe which has been introduced into America compara- 

 tively recently. Its resemblance to Flax is indicated by its 

 common name. The flowers and seeds, however, are much 

 smaller than those of Flax. In appearance and habit of 

 growth, it also bears a general resemblance to Shepherd's 

 Purse and Peppergrass. Like these weeds, it may be 

 either an annual or a winter annual; that is, the seeds may 

 germinate in spring and blossom the same season, or they 

 may germinate in autumn, the plants living through the 

 winter and blossoming the next season. As a rule, it is 

 only the latter that mature their seeds, the season in the 

 Northern states being too short for the seeds of those 

 plants that germinate in spring to reach maturity. 



False Flax is generally introduced as a mixture in flax 

 seed, clover seed, and various grass seeds ; consequently all 

 such seeds should be carefully examined before being sown. 

 When the pest has become established, rotation with a hoed 

 crop is necessary to exterminate it. 



Weeds of Other Families 



The Cockle or Corn Cockle is a well-known pest in grain 

 fields. Its presence is generally due to impure seed, the 

 black seeds of the Cockle being sown with the wheat or 

 other grain. It is an annual, so that it causes little trouble . 

 unless sown with the seed. It grows to a height of three 

 or four feet, and has a slender stem with very few branches, 

 each of which bears on its tip a good-sized reddish-purple 



