374 WEEDS. 23. 



Their ROOT-LEAVES, by fpreadlng upon the 

 furface and feeding in the foil, are injurious 

 to corn ; and among early-fown wheat the 

 plants may get fufficiently flrong in autumn, 

 to run up to feed the enfuing fummer. Alfo 

 corn fown on one plowing may be injured by- 

 this clafs of weeds furviving the operation 

 and rifing between the furrows. 



The bed implement for deflroying the 

 biennial thiflles is the spadle, or a fmall 

 iiOE, taking ofr the crown of the root fome- 

 what within the furface of the ground. The 

 root periflies, and the extirpation is of courfe 

 iinal. 



Corn Scadious, Corn Knobweed, Mil- 

 foil , a n d other ftrong- roated perennial weeds ^ 

 may be ranked among the moft hardy ene- 

 mies of arable crops. 



A dock may in proper fetifon be drawn : 

 its root is taper, brittle, and runs to a definite 

 depth. But the roots of the plants under no- 

 tice are, at fome feafons, as tough as leather, 

 running, in a rope-like cylindrical fliape, to 

 almoft: any depth. To draw them, when, 

 ihey arc fully cflablifhed in the foil, is im- 

 poffible I and if they be broken off or cue 



within 



