284 
E. J. Salisbury 
It will be seen from the subjoined table that the ratio given by 
dividing the length of the periphery of the leaf by the total cross 
sectional area of the vascular lumina is so close in the majority of 
cases between individual members from the same node, that we 
can only conclude a definite relation exists between the transpiring 
surface and the xylem development. The ratio is seen to vary 
within the species as much as 22%, but as between distinct species 
the differences are very much greater. The maximum divergence 
amounting to 3,000% is shewn by Clematis on the one hand and 
Bignonia on the other. 
Greenhouse Plants. Transpiration of Periphery. 
Clematis sp. (mesophyte). 
Leaf. 
Measurement of 
periphery =4>. 
Xylem 
area=*. 
No. of Vessels. 
Ratio - 
X 
A 
37-8 cms. 
6 35 sq. mm. 
216 
5-7 » 
B 
33-6 ,, 
5-78 
193 
5-8 ) 
C 
34 2 
6-30 
194 
5-4 1 
D 
34-2 ,, 
604 
160 
5-6 ( 
E 
30-8 ,, 
6-33 
171 
4-8 | 
F 
30-0 ,, 
688 
J 1 » > 
160 
4-3 ) 
Bignonia sp. (small leaved with hairy surface). 
Leaf. 
Measurement of 
periphery=/. 
Xylem area=*. 
No. of Vessels. 
. b 
Ratio — 
X 
A 
24 4 cms. 
0-116 sq. mm. 
73 
210 1 
215 \ 
B 
20-5 ,, 
0-095 ,, 
75 
C 
22-1 ,, 
0-099 ,, ,, 
77 
223 | 
D 
21 0 ,, 
0 097 ,, ,, 
63 
216 1 
E 
22-4 ,, 
0-108 ,, ,, 
91 
207 | 
F 
21 -4 ,, 
0104 ,, ,, 
78 
205 J 
Clerodendron sp. 
Leaf. 
Measurement of 
periphery=/>. 
Xylem area=.r. 
No. of Vessels. 
Ratio - 
X 
A 
21*1 cms. 
1 -93 sq. mm. 
50 
10-9 1 
B 
18-7 „ 
L76 ,, ,, 
63 
10-6 1 
C 
18-4 ,, 
2-00 „ ,, 
60 
10-8 l 
D 
155 ,, 
1 -71 ,, ,, 
61 
11-01 
E 
20-5 ,, 
2-58 ,, ,, 
70 
12-5 i 
F 
180 ,, 
247 ,, „ 
40 
13-7 ( 
