68 FARM GRASSES OF THE UNITED STATES 
* Kentucky blue-grass, it often contains dog-fennel (A7- 
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 rye-grass is sometimes used. These 
seeds cost about half as much as orchard-grass, and 
resemble it so closely that the adulteration is .only 
detected 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 buyer 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 slightly 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 practi- 
cally all sold as Kentucky blue-grass seed. 
