74 



REGENERA TION 



act more energetically in young twigs, and the buds that develop 

 in the older twigs must arise in antagonism to the action of this 

 force." The polar difference between apex and base is present, 

 nevertheless, as Vochting's experiments show, even in quite old 

 pieces. 



A series of experiments was carried out with the internodes of several 

 plants in order to see if, in the absence of pre-formed buds, new buds 



FIG. 33. After Vochting. A. Internodal piece of Begonia discolor. Apex upward. B. Same 

 with apex downward. C. Internodal piece of Heterocentron diversifolium. Apex upward. 

 D, E. Pieces of leaf of Heterocentron diversifolium. Apex downward. F. Same with apex 

 upward. D, E, F. Same planted in earth. 



would develop. The experiments were undertaken in order to ascertain 

 whether the same polarity, exhibited by longer pieces, would be also 

 found in internodal pieces. In most plants pieces of this kind do not 

 produce new structures, but in Heterocentron diversifolium an internode 

 produces roots at its basal end without regard to the position of the 

 piece (Fig. 33, C). Leaves do not appear on these pieces. On the 

 other hand internodes of Begonia discolor give the opposite result, as 



