AGRICULTURAL SEEDS, SELECTION AND TESTING 271 



2. The weed seeds, separated as above, should then be identified by the use of 

 illustrations and comparison with the laboratory collection of weed seeds. 



3. Seeds, which germinate quickly (3-4 days), should be used for the purpose of 

 testing the viability of seeds and learning the technique of the test. The simplest ar- 

 rangement is to use the blotter pads previously described by placing alternately wet pads 

 and layers of seeds between two deep soup dishes, one of them being inverted over the 

 other (Fig. 1 1 8). The rag doll seed tester may also be used. Secure muslin cloth of a 

 good quality and tear into strips from eight to ten inches wide and three to five feet 

 long. Where these strips are to be used very much, the edges should be hemmed to 

 prevent raveling. Squares can then be marked with a heavy pencil on the cloth, so 

 that they have a three inch side. The seeds are then placed on the square and the 

 cloth rolled up, so as to inclose the seeds. The whole roll is then placed in water for 

 a few hours and then removed and kept moist until germination begins. In both of 

 these methods of testing the germination of seeds, if one hundred seeds are used, 1 the 

 number that germinate within the specified time will give the exact percentage^of 

 viability without calculation. 



