PERENNIAL FORAGE GRASSES 21 



require about seven days. Among leguminous seeds, especially 

 clover seeds, the presence of hard or dormant seeds is common. 

 On account of the structure of their seed coats or of their 

 chemical composition, they do not readily absorb water and 

 hence do not germinate within seven days, although they do 

 so later. It is usual to add one-half to one-third the per cent, 

 of hard seeds remaining to the percentage of germinating 

 seeds. In red clover the number of hard seeds is generally 

 7 to 9 per cent. They are said to be more common when the 

 seed crop is good and to be more frequent among dark clover 

 seeds. It has been found that scratching or rubbing the surface 

 makes them more easily germinable, and it is said that friction 

 is sometimes practised by seedsmen for this purpose. 



Germination tests are carried on either between or upon 

 flannel cloth or blotting paper or in beds of sterilized sand 

 free from organic matter. The small seeds do best when placed 

 upon, the large ones when placed between the media. Ex- 

 perience has shown which gives the best results in the case of 

 each species. In seed control stations the seeds from 100 to 

 400, after being placed upon or between the cloth or blotter, 

 are put in a germinating apparatus where the temperature 

 is under control. (C. A. 476) For private tests the cloth, 

 blotter, or sand may be placed between dinner plates, kept in 

 a room that does not fall below 50 F. at night and is between 

 60 and 70 F. during the day. 



19. Grass Mixtures. The desirability of sowing two or more 

 kinds of grass seed together must depend largely on the 

 adaptability of the grasses to the locality and the purpose for 

 which the crop is grown. For hay the plants should mature 

 at about the same time. It may be laid down as a rule that 

 for hay it does not pay to grow one plant with another when 

 it is not in itself adapted to the conditions under which it is 

 grown when sown alone. If it does not pay to sow alone it 

 will not pay to sow with another crop. The introduction of 



