20 



THE VITALITY AND GERMINATION OF SEEDS. 



the stronger the vitality of the original sample of seed the more harsh 

 treatment can be undergone without being injured. Strong vitality 

 implies long life as well as vigorous seedlings. 



Another very important factor to be considered in the handling of 

 seeds is the relative resistance of seeds of various species to adverse 

 conditions. Certain seeds under one set of conditions may retain 

 their vitality exceedingly well, while seeds of other species of plants 

 under identical conditions may be killed in a comparatively short time. 

 For this reason no general rule can be laid down for the preservation 

 of seeds. Table V shows the varying degrees of deterioration of the 

 different species of seeds used in the experiments. 



TABLE V. Different degrees of deterioration of various kinds of seeds. 



In the above table the list of seeds is arranged in the order of their 

 power to withstand the action of diverse climatic conditions, as shown 

 by the results of the second test, given in Table II. Tomato seeds 

 were found to be the most resistant, the control sample germinating 

 97. 5 per cent. The average germination of the samples of tomato seed 

 kept at the various places was 92.43 per cent, or a loss in vitality of 

 only 5.20 per cent. The seed showing the next least injury was the 

 peas, with a deterioration of 11.39 per cent. The phlox, which was the 

 most affected by the unfavorable conditions, germinated only 7.62 per 

 cent, thus showing a loss in vitality of 85.85 per cent. 



It is also interesting to note that the order, as shown by the second 

 series of tests, is quite different from that of the first. This lack of 

 uniformity increases the difficulties that must be overcome before the 

 causes of the loss of vitality in seeds can be fully comprehended. Were 

 all seeds affected in the same way when subjected to identical con- 



