184 YEARBOOK OF THE U.'S. DEPARTMENT OF AGRICULTURE. 



of difference between its germination and that required by the 

 standard. 



The following table is offered provisionally, having been made up 

 from original data and the most reliable outside sources. A great 

 deal of experimenting will be necessary before a permanent table of 

 germination standards is offered: 



Table of germination standards. 



Nothing has been said in this article about testing seeds for purity. 

 This is an important matter, but could not be properly treated in a 

 few pages. Garden and flower seeds ought always to be nearly pure, 

 but those of grasses and forage plants, especially clovers, frequently 

 contain a considerable amount of foreign matter. The seeds of harm- 

 ful weeds are often found in quantity in clover seed. Farmers 

 should be on their guard against impure seeds. 



