No. 4.] MASSACHUSETTS WEEDS. 277 



money-wort. It is used even strong enough to kill the grass, 

 but new grass will eventually come up at the exclusion of the 

 money-wort. The three-fingered crab-grass is seen abun- 

 dantly late in summer, and appears to be spreading. We 

 know of nothing to recommend for this. 



The introduction into our fields of such weeds as chess, 

 charlock, etc., is due to impure seed. 



Another method, therefore, of checking manj^ weeds, and 

 one which would appear to be a very logical one, would be 

 to start with pure seed. We have not in this country quite 

 waked up to the necessity of buying pure seed, or of even 

 buying seed of a guaranteed germination. 



Some of our grass weeds can be controlled bv mowinsr 

 them just before they go to seed. One field at the Agricult- 

 ural College which was densely covered with the white daisy 

 a few years ago has, by this method of treatment, become 

 almost completely rid of this plant. Other field weeds are 

 more difficult to eradicate by this method, as their time of 

 maturing seed does not correspond with the time of mowing 

 grass. 



