1915] LOEB—REGEN ERATION 257 
about 50 per cent of the cases formed roots and shoots in its 
notches rather rapidly. This happened often, but not always, when 
the formation of shoots on the stem itself was long delayed. UIti- 
mately all the leaves may form adventitious roots and shoots in 
the notches that are under water or near the edge of the water. 
This experiment, therefore, supports the conclusion that if the 
buds of the stem grow out very rapidly, their growth inhibits or 
ie 
Fics. 12 AND 13 
* 
delays the growth of roots and shoots in the notches of the leaf 
attached to the stem. 
Figs. 12 and 13 are a repetition of the same experiment. The 
drawing was made 17 days after the beginning of the experiment. 
The stem in fig. 12 formed rapidly two shoots (SS) from its apical 
buds and this inhibited the growth of roots and shoots in the 
submersed leaf; in fig. 13 the stem formed no shoots and the sub- 
mersed leaf could form roots. The root formation in both stems 
