226 



Physiological Pre-determiyiation 



Lot II. Seeds from which one half of one of the cotyledons was 

 removed; 



Lot III. Seeds from which one whole cotyledon was removed; 



T^ot IV. Seeds from which 1 J cotyledons were removed. 

 The seeds were then planted in uniform soil and received similar 

 cultural methods. Morphological differences manifested themselves 

 throughout the course of development. The suppression of a part of the 

 food-reserves of the seed resulted from the outset in a retardation in the 

 growth of the stem which lasted throughout the life of the plant. This 

 fact is brought out in the following table, where the mean height of the 

 stems of the beans and vetches at the end of the first three months of 

 their development is indicated. 



Table III. 



Mean height of stem after 



The number and size of the leaves and also the total fresh and dry 

 weights of the aerial parts of the plants at each stage in their develop- 

 ment remained approximately proportional to the amount of reserve 

 food-material originally at the disposal of the embryo, as the following 

 figures show : 



Table IV. 



Number of leaves produced after 



