186 



CRUCIFERAE (MUSTARD FAMILY) 



A special pest in grain fields, as its early season of bloom enables 

 it to foul the ground with its seeds before the grain is ready to 

 harvest and the smooth, glaucous foliage renders it impervious to 

 injury from sprays that would not also kill the accompanying crop. 

 Stem one to four feet tall, erect, rather 



stout, with few branches. Lower leaves 



pinnatifid, with terminal lobe very large, 

 coarsely toothed, and with long petioles ; 

 upper leaves oblong, nearly entire, tapering 

 to the base, all light green, rather thick, 

 smooth, and glaucous. Flowers bright yellow, 

 more than a half-inch broad, clustered at 

 the top of racemes, which, before the pods 

 are all formed, often become more than 

 a foot long. Siliques one to two inches 

 long, nearly a third of their length taken 

 by a slim, awl-shaped, empty beak. Seeds 



. globular and brown. (Fig. 129.) 



Means of control 



Harrow young seedlings from grain fields 

 with a weeding harrow. Plants that survive 

 the treatment should be hand-pulled while 

 in early bloom. If seeds have matured and 

 fallen, stubbles should be burned over for 

 the purpose of destroying them. Plants of 

 roadsides and waste places should also be 

 pulled or cut before seed is formed. 



FIG. 129. Indian 

 Mustard (Brassica 

 juncea). X i- 



WHITE MUSTARD 



Brassica alba, Boiss 

 (Sinapis dlba, L.) 



Introduced. Annual or biennial. Propagates by seeds. 



Time of bloom : June to August. 



Seed-time: July to September. 



Range: Locally in most parts of North America except the far 



North. 

 Habitat: Cultivated ground, waste places. 



