EXTERMINATION OF WEEDS 583 



seeds before the leaves appear, and are often overlooked until 

 the mischief is done. The prevention of seeding by cutting off 

 the inflorescence or flower-bearing axis is not always a total 

 destruction, as explained below. It must also be pointed out 

 that some plants, thistles especially, are able to perfect their 

 seed on a cut stem after it has been severed from the root, if 

 this is not done until the flowering is well advanced, the nutritive 

 material necessary for the ripening of the seed being already in 

 the stem. 



The prevention of the seeding of weeds should not be confined 

 to those found in the cultivated land : it is equally important to 

 keep weeds down on roadsides, near hedges, and on waste 

 ground. It is very frequently noticed that the smaller the area 

 of the fields — and consequently the more hedges — the larger the 

 number of weeds on the fields ; and this is chiefly due to the fact 

 that weeds in the hedges are often neglected. 

 ' {b) Every effort should be made to avoid the sowing of weed 

 seeds inadvertently. The use of pure seed is a matter of great 

 importance; in fact, everything that is placed upon the land 

 should be free from admixture with weed seeds. Special atten- 

 tion should be paid to the manure-heap, composts of all kinds, 

 and the disposal of screenings, sweepings from hay-lofts, and 

 other refuse likely to contain weeds, should receive careful con- 

 sideration. 



If weeds from hedges and arable ground are placed on 

 manure or compost heaps to rot, it is more satisfactory to apply 

 such manure to grass land rather than to arable ground, as in 

 the former case the seedlings are rapidly crowded out by the 

 established pasture plants with which they must compete. Many 

 weeds are rarely or never seen except on arable ground, and it 

 would appear that certain conditions necessary for their exist- 

 ence are not present in ordinary pasture. 



Destruction by fire, however, is the most perfect method of 

 disposing of weeds, and should be adopted wherever possible, 



