100 FARM WEEDS OF CANADA 



WORM-SEED MUSTARD (Erysimum cheiranthoides L.) 

 Other English name : Treacle Mustard. 



Native. Annual and winter annual. Stems erect, simple 

 or branching, 6 inches to 2 feet high. Whole plant sometimes 

 slightly hoary with short, star-like hairs. Leaves dark green, 

 lance-shaped, sparsely toothed. Flowers bright yellow, 1/5-inch 

 across, in terminal clusters about 1 inch across, on gradually 

 elongating racemes. Seed-pods slightly curved, from 1/2 to 1-inch 

 long, obtusely 4-angled, erect on spreading footstalks. Each 

 pod contains about 25 seeds. An average plant will ripen 

 about 25,000 seeds. 



The seed (Plate 74, fig. 42) varies somewhat in size and 

 shape, generally pointed at one end, rounded at the other, about 

 1/24 of an inch long, reddish yellow, with a dull surface but 

 almost destitute of mucilage. Scar end darkened. The miniature 

 root of the germ is conspicuous. The seeds are very bitter. 



Time of flowering: June to autumn; seeds ripe July to frost. 



Propagation: By seeds. 



Occurrence : Frequent in waste places and on cultivated 

 land throughout Canada. 



Injury: On account of the pungent flavour, stock will refuse 

 to eat grain in which these seeds are present in any appreciable 

 quantity. It is a common weed in clover fields and is avoided 

 by all farm stock, except sheep, either in pasture or in cured 

 hay. If neglected, it will grow in dense masses and crowd out 

 crops. The seeds are frequently found in grass and clover seeds. 



Remedy: The seeds are short-lived, and this mustard is 

 kept well under control on land worked under a short crop 

 rotation with clean cultivation. In districts where cereal 

 grains predonimate, the cultivation of bare stubble land, as 

 recommended for other mustards, followed by discing in the 

 spring before seeding, will keep this pest in check. The seeds 

 can be cleaned from clover seed by screening. 



