468 BOTANICAL GAZETTE [JUNE 
the strength of the tendril. This may be explained by the sup- . 
position that a weight of 20 grams does not exert a pressure much 
greater than is caused by the contraction of the contact portion 
of the tendril when coiled about a support. 
Ligatures were also tied about tendrils in different regions to 
determine the effect of contact in a more and in a less sensitive 
part of the tendril. The effect of these ligatures in regions a and 
b, respectively, upon the breaking strength is shown in table VIII; 
-@ was about one-third the length of the whole tendril from the 
apex, and } the same distance from the base of the tendril. 
TABLE VIII 
PERIOD 32 DAYS 
LIGATURE AT a LIGATURE AT 6 
Tendril Breaking strength Tendril Breaking strength 
B, 230 grams Hg 590 grams 
Ds 550 Hyo 3 
Dy 510 Hu 160 
I, 490 K, 140 
Ig 650 K; 225 
J, 650 Ke 269 
J 70° 
Js 665 
L, 510 
M; 600 
M, 75° 
Averages 573 281 
These results show that a ligature placed in a more sensitive 
region (a) calls forth a greater formation of mechanical tissue than 
when placed in a less sensitive region (6). This accords with the 
former inferences made in experiments on the middle third and 
basal third. 
RESULTS IN BREAKING STRENGTH 
The following conclusions may be deduced from the foregoing 
results in breaking strength of tendrils: 
1. Contact alone plays an important part in giving strength 
to the tendril. 
