77 2 Journal of Agricultural Research vol. vi, No. 20 



It should be added that no change could be detected in the viability 

 of the seeds during the interval between the two tests except in case of 

 the machine-hulled lots of red-clover seed and of alfalfa seed. With 

 these there was a very slight decrease in viability. 



INFLUENCE OF MATURITY ON THE RATE AT WHICH IMPERMEABLE RED- 

 CLOVER SEEDS BECOME PERMEABLE IN MANILA ENVELOPES 



Four lots of red -clover seed were gathered in July, 1910. This was 

 the earliest seed of a good grade that could be obtained from the plants 

 in question. Four other lots of seed were gathered from the same culti- 

 vated rows of plants in October, 1910. 



The average percentages of impermeable seeds in the lots of seed 

 gathered in July and in October were, respectively, 71 and 82. When 

 again tested for germination two years later, the average percentages 

 of impermeable seeds were 35 and 62. In other words, one-half of the 

 impermeable seeds in the less mature lots which were gathered in July 

 and one-fourth of those in the more mature lots which were gathered 

 in October became permeable in two years. There was practically no 

 change in viability during the two years. 



COMPARATIVE RATES AT WHICH IMPERMEABLE SEEDS BECOME PERMEABLE 

 IN WET BLOTTERS AND IN DRY STORAGE 



A comparison of Tables III and IV shows that impermeable seeds 

 become permeable more rapidly when kept under germination condi- 

 tions than when stored dry. The difference in rates varies widely among 

 different lots of the same species. 



Between 20 and 40 per cent more of the majority of the lots of hand- 

 hulled red-clover seed remained impermeable after four years in dry 

 storage than after four years in wet blotters. With a few lots of red- 

 clover seed, however, the differences were less than 5 per cent, and with 

 a few other lots the differences were between 50 and 60 per cent. 



Figure 3 represents graphically the changes in the percentage of im- 

 permeable seeds of typical lots of red clover, alsike clover, sweet clover, 

 and alfalfa seed when kept in wet blotters and when stored dry in manila 

 envelopes for various periods. 



1. With each species the percentage of impermeable seeds decreased 

 more rapidly in wet blotters than in dry storage. 



2. The percentage of impermeable seeds decreased more rapidly during 

 the first year than during succeeding years both in wet blotters and in 

 dry storage. 



PRODUCTION OF SEEDLINGS IN SOIL BY IMPERMEABLE LEGUMINOUS SEEDS 



Comparative tests were made in germinating chambers, in a greenhouse, 

 and in soil outdoors, using lots of seed with varying percentages of 

 impermeable seeds. The results of these tests indicate that, with rare 



