7H 



Some Common Thistles. [march, 



year, namely, in autumn and spring for the eradication of the 

 young plants, and in June or July for the destruction of the 

 old ones so as to prevent seeding, is all that is necessary in the 

 case of the three kinds of thistles mentioned. 



(2.) Destruction of Creeping Thistle. — The creeping thistle, 

 however, cannot be destroyed by the adoption of such 

 methods. Seeding must, of course, be prevented, but to 

 wait until June or July before cutting is an excellent way of 



1 23 4 



Fig. 9. — Flower-Heads of Thistles (natural size). 



1. — Creeping Thistle (anthers perfect). 2. — Creeping Thistle (anthers abortive). 

 3.— Marsh Thistle. 4.— Welted Thistle. 



keeping these pests in a state of robust health. During the 

 summer the plants manufacture a large amount of food- 

 material in their leaves, and this is transferred and stored 

 below ground in the roots and buds upon the latter. Com- 

 paratively little seed is produced, and little of this stored 

 food is needed for it. To cut off the stems after this storage 

 has taken place has no exhausting effect on the crop, and the 

 mowing of this kind of thistle once or twice late in the season 

 can be practised for years without diminishing its vigour. To 

 cope with the creeping thistle it must be cut early in the 

 year, soon after it comes above ground, and the cutting should 

 be repeated as frequently as possible throughout the season. 



