306 BULLETIN 312 



trated sulfuric acid for 60 minutes these seeds were again placed in the 

 germinator, with the result that 68 of them had germinated at the end 

 of 4 days, and 71, or 98.6 per cent, at the end of 7 days. 



From 87 to 100 per cent of the seeds in most lots, treated as shown in 

 Table 4, had germinated after 4 days. All ungerminated seeds, however, 

 were left longer in the germinator and counts were again made at the 

 end of 7 and 14 days, with the results shown. 



From an inspection of this table it is seen that Lots 1-3-1 and 1-3-2 

 had been previously treated with concentrated sulfuric acid for 1 5 minutes ; 

 and that Lots I-s~(3, 4, and 5) had received such treatment fpr 30 or 

 60 minutes. These seeds after being again treated with acid (with the 

 exception of those marked " D," which were soft, decayed, and doubt- 

 less dead when put into acid) gave 100 per cent germination. 



This would seem to show quite conclusively that treatment of clover 

 seed with concentrated sulfuric acid will often hasten germination, or 

 will even make germination possible when otherwise it would be much 

 delayed or would never occur. 



After these lots of clover seed had been in the germinator 14 days, as 

 shown in Table 4, final counts were taken. It was seen that there still 

 remained a few ungerminated seeds, which were bright, hard, and appar- 

 ently alive. In order to test these few seeds further, a number of them 

 were treated again with concentrated sulfuric acid for 30 minutes, after 

 which they were thoroughly washed in water and again placed in the 

 germinator. The results are shown in Table 5. 



It is seen that every seed except 5 had germinated at the end of 3. .days. 

 The five not germinated were apparently alive, but were not tested longer. 



These tests, besides showing that sulfuric acid treatment of clover seed is 

 often beneficial to hasten and produce germination, show that some seeds 

 require acid treatment for a considerable length of time: 15 or 30 minutes 

 is sometimes not long enough. They also show the great resistance that 

 some clover seeds have to the action of water on their seed coats. Some 

 of the seeds experimented with were between moist blotters for 21 days 

 without germinating; then they withstood the action of concentrated 

 sulfuric acid for 30 to 60 minutes and were 14 days between moist blotters 

 without germinating. On further treatment with concentrated sulfuric 

 acid for 30 minutes (as shown in Table 5), practically all of these most 

 resistant seeds germinated. 



Effect of treatment for different lengths of time 



In order to determine the length of time during which clover seed could 

 be left in concentrated sulfuric acid (sp. gr. 1.83) without injury, several 

 experiments were tried, the results of which are given in Tables 6 and 7. 



