1916] LOEB—BRYOPHYLLUM 301 
will take place in the notches. Instead a strong shoot (S) has been 
formed from the axillary bud of the leaf which had been removed. | 
The “suction” effect of the complete stem or of the growing bud 
was strong enough to inhibit the growth in the notches of the leaf 
completely. 
All these statements 
can easily be verified. 
Some variation is met 
in specimens of the type 
of fig. 14, inasmuch as 
very often only the roots 
will grow out from the 
notches, while the shoots 
will not develop beyond 
tiny beginnings. . . 
In all the experi- % SSSEEEEEES 
CLOSES 
ments we have thus,far SS SSS = 
described the suction 
effect of the stem inhib- 
ited the growth of the notches of the leaf. If the theory be correct 
that it is only the sap flow to or from a dormant bud which deter- 
mines whether the latter will grow or 
continue in a resting condition, the 
reverse experiment should also be 
possible; namely, that by accelerating 
the growth of notches in a leaf it 
should be possible to inhibit the 
growth of buds on the stem. From 
all that has been said this experiment 
could only meet with success where 
the suction effect of the stem is moder- 
ate. Two leaves of the same node are 
hag - cut from the plant, the cortex of the 
Piece of stem is cut lengthwise and the wood taken out from the stem 
(fig. 16). This leaves two leaves connected only by the cortex of the 
stem (fig. 16). The leaves are placed with their tips under water 
to induce a rapid growing out of the notches at the tips of the two 
Fic. 16 
