196 Peculiar Growth Habit and the Anatomy of Dog’s Mercury . 
growth habit may arise as a result of the discontinuity of 
growth of the apical meristem. 
The number of additional leaves formed after flowering 
seems to be about the same in both male and female plants, 
varying from one to five pairs. The leaves of the male plant 
are, however, larger, and a considerable difference in the 
length of stem bearing the additional leaves was observed, 
as shown in Tables 1-4. 
TABLE 1. 
Measurement, in cms., of the length of the basal vegetative, 
middle inflorescence, and terminal vegetative regions of female 
plants of Mercurialis perennis. In shaded position. 
Basal region 
below B [ fig . 1). 
Flowering region 
between A and B . 
Terminal region 
above A . 
Total . 
18-0 
6-5 
i -5 
26-0 
19-7 
3-5 
3-2 
26-4 
18-1 
5'4 
i-i 
24-6 
l8 ‘2 
6-6 
4'3 
29-1 
18-6 
7-0 
i -5 
27-1 
17-8 
9-0 
3 -o 
29-8 
18-1 
5‘4 
4 *7 
28-2 
17-4 
7-0 
i -5 
25-9 
I 5 H 
7-8 
3-4 
26-6 
18-2 
6-7 
5-6 
30-5 
I 5'9 
8-2 
3-8 
27-9 
17-9 
4-6 
3-2 
25-7 
19-7 
4-3 
2-4 
26-4 
18-8 
6-9 
4-3 
3 °'° 
Mean ... 17-99 
6-35 
3 " 11 
27'45 
TABLE 
2. 
Measurement, in cms., of the length of the basal vegetative, 
middle inflorescence, and terminal vegetative regions of male 
plants of Mercurialis perennis. Growing close to plants in 
Table 1. 
Basal region . 
Flowering region . 
Terminal region . 
Total . 
21-5 
4-6 
11 -i 
37-2 
17-7 
6-6 
12-2 
36-5 
22-9 
3-4 
8-i 
34-4 
24-8 
6-8 
7-8 
39-4 
15-9 
. 5-8 
14-7 
36-4 
18-6 
9-1 
12-9 
40-6 
24 '7 
4-2 
9-4 
38-3 
16-6 
11 -i 
6-i 
33-8 
23-2 
4-4 
9-5 
37 -i 
17-2 
16-2 
6-9 
4°'3 
18-6 
5-6 
9-8 
34 -° 
16-4 
13-5 
11 '4 
4 i -3 
18-3 
5-4 
n -5 
35-2 
I 5 ‘ I 
4‘3 
13-2 
32-6 
Mean ... 19-39 
7-21 
io -33 
36-93 
The Naturalist 
