STIMULATION IN THE LEAVES OF DIONAEA 
75 
to the last dot, was only 3.1 percent for this entire period, which is 
much less than the enlargement in the same direction shown by the 
lower surface of stimulated leaves for the much shorter period of 
closing and reopening. The second experiment lasted seven days 
and the total expansion recorded was 1.4 percent. The third experi- 
ment also continued seven days, but showed a greater amount of total 
enlargement than did either of the other two, this being 9.6 percent. 
If the percentage of total transverse enlargement of the ventral surface 
of the leaf lobe be divided by the number of days in each case, the 
Table V 
Comparative Measurements of Distances Between Adjacent Dots on the Lower Surface of 
Unstimulated Dionaea Leaves, the Dots Arranged in a Line Transverse to the 
Midrib, to Show Rates of Transverse Enlargement 
Experiment No. 
At Be- 
ginning 
of Ex- 
peri- 
ment 
After 
I 
Day 
After 
2 
Days 
After 
3 
Days 
After 
Days 
After 
6 
Days 
After 
Days 
After 
8 
Days 
After 
ID 
Days 
After 
18 
Days 
Total 
En- 
large- 
ment 
[a 
\b 
I ^ c 
\d 
{e 
Between extreme dots 
22.0 
25.0 
30-5 
33-0 
18.0 
22.0 
25.0 
30-5 
33.5 
18.0 
23.0 
25.0 
30.0 
33-3 
18.0 
23.0 
26.0 
30.5 
33.0 
18.0 
22.0 
26.0 
31.0 
33-0 
18.5 
22.0 
26.0 
31.0 
33.0 
18.0 
22.0 
26.0 
31.0 
33-0 
18.0 
22.0 
26.0 
31-5 
34-5 
18.5 
Per- 
cent 
0.0 
4.0 
3- 3 
4- 5 
2.8 
3-1 
0.0 
1-5 
3-9 
0.0 
1.4 
II. I 
5- 2 
8.0 
14-3 
9.6 
[a 
27.0 
33.5 
26.0 
19.0 
27.0 
33-5 
26.0 
19.0 
27.0 
34-0 
27.0 
19.0 
27.0 
34-0 
27.0 
19.0 
H^:;;::::::;;;::: 
[d 
Between extreme dots 
[a 
13.5 
19.0 
25.0 
21.0 
13-5 
19.0 
25.0 
21.0 
15.0 
20.0 
26.5 
23.0 
15.0 
20.0 
27.0 
24.0 
3h;:;;::::::::;::: 
[d 
Between extreme dots . 

average daily rates for the three cases prove to be: 0.17, 0.20, and 
1.36 percent, respectively. The highest of these average daily rates 
is only 43.7 percent of the smallest corresponding total enlargement 
recorded for the period of closing and opening in the case of stimulated 
leaves. The average daily rate of increase in the distance between the 
extreme dots on the lower surface in the case of unstimulated leaves 
