THE MUSTARD FAMILY 83 



The seed (Plate 73, fig. 30) is about 1/16 of an inch in 

 length, bright reddish-yellow, egg-shaped in outline, much 

 flattened, blunt on the straight side and very thin or slightly 

 winged on the rounded side ; both sides show a rather deep 

 groove in the middle. When moistened the seeds develop a large 

 amount of mucilage. Although there are only two seeds in a 

 pod, each plant produces thousands of seeds. 



Time of flowering: June, July; seed ripe on early plants 

 by the end of June. 



Propagation: By seeds. 



Occurrence: Widely distributed throughout the Dominion. 

 Most abundant on light sandy soils in eastern Canada. 



Injury: In the West it crowds out grain crops grown on 

 stubble, particularly on light land and in a wet spring. This is 

 from the autumn plants, which get a start before the grain and 

 choke it out with their thick, vigorous growth. It gives trouble 

 in clover fields and new meadows where the crop is winter killed. 

 The seed is a frequent impurity in grass and clover seeds. 



Remedy: Only the autumn plants which live through the 

 winter give trouble in grain. Thorough surface cultivation in 

 the spring, with the plow, disc or broad-shared cultivator, 

 is efficacious. Immature seeds may ripen in the pods when 

 plowed down. Badly infested fields in the eastern provinces 

 should be disced or plowed directly after harvest, cultivated 

 from time to time until winter, and again until late in June, 

 when they may be planted, or sown with a late fodder crop. 



ALLIED SPECIES: Field Peppergrass or Cow Cress (Lepi- 

 dium campestre (L.) R. Br.). A biennial yet rare in Canada, 

 occurring in the clover-growing districts of Ontario. The 

 plant grows with two or three stems from the same root. These 

 are branched above, forming corymbs, with a few nearly erect 

 branches. The lower leaves are oblong and toothless; those of 

 the stem are spear-shaped with blunt ends, afew have large, shallow 



