72 
WILLIAM H. BROWN 
Table III 
Comparative Measurements of Distance Between Adjacent Dots on the Upper Surface 
of Dionaea Leaves Before and After Closing and After Reopening, the Dots 
Arranged in a Line Transverse to the Midrib, Together with Percen- 
tage of Shrinkage During Closure and of Expansion During 
Reopening 
Experiment No. 
Distances, 
Distances, 
Shrinkage 
Distances, 
Expansion 
Leaf Open 
Leaf Closed 
Leaf 
Closure 
Reopened 
Reopening 
Percent 
Percent 
19.0 
19.0 
0.0 
20.0 
5-3 

20.0 
19.7 
1-5 
22.0 
11.7 
16.0 
15-8 
1-3 
17.0 
7.6 
[d 
II. 0 
10.5 
4-5 
II-5 
9-5 
Between extreme dots 
1.5 
9-3 
24.0 
24.0 
0.0 
^ ^v;;.;:;:::::::::::::::: 
27.0 
26.8 
0.7 
20.0 
19.7 
1-5 
[d 
15.0 
15.0 
0.0 
Between extreme dots 
0.6 
3 { 
20.0 
19.5 
2-5 
13.5 
15.0 
II. I 
4 ^.v;;.;::;;:::;::::;;;::: 
19.0 
20.0 
5-3 
25.0 
27.0 
8.0 
[d 
21.0 
24.0 
14.3 
.... 1 9.6 
From the data of Table III it appears that these dots on the 
upper surface of the leaf approach each other to a slight degree during 
the closing process. The average decrease thus occurring in the 
distances between extreme dots of these transverse rows is 1.5 percent 
of the original distance. 
This apparent transverse shrinkage of the upper surface may be 
explained by the error of measurement just pointed out, due to curva- 
ture; the bending of the lobe which accompanies closure should bring 
the dots on the upper surface closer together without any actual 
change in the extent of this surface. To test this suggestion, a paper 
marked with dots at measured distances apart was bent so as to have 
a form similar to that of a curved leaf lobe, after which the distances 
between the dots were again measured. In this case the dots ap- 
proached each other to a greater extent than did those on the dorsal 
