REGENERA T1ON 



there may be one or more buds that do not grow ; but if the piece is 

 cut in two just above these buds, they will then grow out. 



The results show that at the base of the piece the same factors 

 that bring about the development of the rudiments of preexisting 

 roots also cause the development of new roots, if the lower end is 

 in a region in which there are no rudiments of roots present. The 



FIG. 32. After Vochting. A. Piece of willow cut off in July, suspended in moist atmosphere with 

 apex upward. B. Older piece of willow (cut off in March) suspended in moist atmosphere 

 with apex downward. C. Piece of willow with a ring removed from middle. Apex upward. 



D. Piece of root of Populus dilatata. Basal end upward. Shoots from basal callus. 



E. Piece of root of same with two rings removed. New shoots develop from basal callus, 

 and from basal end of each ring. 



influence that produces the new roots is confined to the basal part 

 of the piece. In the apical part of the piece there are no adventi- 

 tious structures produced, but a longer region is active, and several 

 pre-formed leaf-buds begin to elongate. The topmost shoot grows 

 faster than the others, showing that the influence that produces the 

 growth is stronger near the apical end than at points further removed. 

 If another piece of a willow stem be placed under the same condi- 



