68 FARM GRASSES OP THE UNITED STATES 



Kentucky blue-grass, it often contains dog-fennel (An- 

 themis cotula), peppergrass, and five-finger. 



Redtop seed usually contains but few weed seeds, 

 among the most common being slender-rush and sor- 

 rel. (The seeds of some of the most common weeds 

 are shown in Fig. 14.) 



ADULTERATION 



A few of our common grass-seeds are frequently 

 and wilfully adulterated. The most important of these 

 are orchard-grass and Kentucky blue-grass. Orchard- 

 grass is most often adulterated with meadow-fescue, 

 although English rj^e-grass is sometimes used. These 

 seeds cost about half as much as orchard-grass, and 

 resemble it so closely that the adulteration is only 

 detedfed on close examination. The velvet-grass seed 

 always found in New Zealand orchard-grass is har- 

 vested with it and not mixed intentionally. 



But few seed-dealers can distinguish Canada from 

 Kentucky blue-grass seed. These two resemble each 

 other so closely that a careful comparative study with 

 a hand-lens is necessary before a person can separate 

 them. 



When a bu>er is offered two lots of seed as Ken- 

 tucky blue-grass, one containing a large percentage of 

 Canada, and the other pure Kentucky', he will usually 

 choose the adulterated sample, because it is brighter 

 and cleaner, and is offered at a slighth' lower price. 

 Although but little Canada blue-grass seed is sold as 

 such in the United States, there is an annual importa- 

 tion of from 450,000 to 750,000 lbs., which is pradli- 

 cally all sold as Kentucky blue-grass seed. 



