782 



Journal of Agricultural Research 



Vol. VI, No. 20. 



move all the seeds. All seeds which had softened and looked healthy 

 were counted as germinated. 



The red-clover seeds which were impermeable when removed from the 

 soil or from the seed heads were subjected to a germination test for one 

 month in a chamber at about 20 C. The seeds which germinated in the 

 germinating chamber were included with those which germinated in the 

 soil in determining the germinating capacity. 



All the alfalfa seeds gathered in the spring were from pods which 

 remained upon the straw a foot or more above the soil. Ninety per 

 cent or more of the seeds in these pods were brown and dead, and some 

 were partly disintegrated. The remaining 10 per cent or less were 

 bright, plump, and yellow. These were retained for the germination 

 test. All alfalfa seeds which could be found in the surface soil under 

 the plants were dead. 



There were included in the examination 9,723 red-clover seeds, 575 

 alsike-clover seeds, 412 sweet-clover seeds, 200 alfalfa seeds, and 99 

 yellow-trefoil seeds, which were gathered in the spring. 



Table X gives the results of the investigations. 



TablU X. — Germination of leguminous seeds after passing the winter on or under the 

 parent plants in the field compared -with the germination of seeds harvested the previous 

 fall 



Kind of seed. 



Red clover. .. 



Do 



Do 



Alsike clover. 



Do 



Sweet clover . 



Do 



Alfalfa 



Do 



Yellow trefoil 



Num- 

 ber of 

 lots. 



Season in which 

 gathered. 



Fall, 1909 . . . 

 March, 1910° 

 March, 1910 s 

 Fall, 1912 . . . 

 April, 1913 c. 

 Fall, 1912 . . . 

 April, 19 13 c . 

 Fall, 1913 . . . 

 April, 1914^. 

 April, 19 13 c . 



Average percentage of- 



Germina- 

 tion. 



66 



37 

 15 

 59 



TO 



63 

 76 



3 

 64 



Imperme- 

 able 

 seeds. 



88 



33 

 61 



84 



37 

 90 

 36 



97 

 36 



Dead 



seeds. 



Calculated 



average 

 percentage 

 of the seeds 

 previously 

 imperme- 

 able which 

 became 

 perme- 

 able. 



I 

 63 

 3° 



— 2 



59 



o From heads embedded in the soil; germination reported includes i month in chamber. 



b From heads on the straw above the soil; germination reported includes i month in chamber. 



c Germination in the field only. 



<* From dry heads well above the soil; germination in chamber. 



i. From 52 to 63 per cent of the clover and yellow-trefoil seeds which 

 were impermeable in the fall softened after passing the winter in the soil. 

 Of the impermeable red-clover seeds which were in heads several inches 

 above the soil 30 per cent softened. In the meantime only 1 per cent 

 of the impermeable red-clover seeds which were stored in the laboratory 

 over the winter became permeable, and the percentage of alsike-clover 



