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H. S. REED AND F. F. HALMA 



of amputation was greater. In few cases is the disparity so 

 great as in figure I, A, where the second shoot started some time 

 later than the first. The smaller size of the inferior shoots ap- 

 pears to be due to the effect of the growth-inhibiting substance 

 produced in those above, an effect to which each shoot contrib- 

 utes, with the result that the lowest buds are entirely prevented 

 from developing. 



Fig. 2. Regeneration of shoots on a pear branch which was twice pruned. 

 In the winter the branch was cut at A, and in the following July the upper three 

 shoots were cut off at B. 



The discussion thus far has been based upon the phenomena of 

 growth in upright shoots. It will be next in order to examine 

 the behavior of shoots in horizontal position to see whether the 

 above assumptions are confirmed or contradicted. 



Figure 3 shows an instructive case. The branch there shown 

 was originally vertical. The main axis, which grew slowly, rep- 



