Carbon Assimilation. 
1 8 [ 
Table XVII. 
Assimilation Numbers of Leaves of the Same Species 
at different times in Spring. 
25° 5% C0 2 . 48,000 lux. 
Date. 
Species. 
Weight 
of 
Leaves 
gm. 
Dry 
Weight 
gm. 
Leaf 
Surface 
cm *. 
Chloro¬ 
phyll 
mg. 
CO, 
per hr. 
gm. 
Ass. 
No. 
29th April 
Aesculus 
8 
1-68 
211 
81 
0 090 
Ill 
7th May 
Hippo- 
8 
1-65 
374 
121 
0146 
12*1 
3rd June 
castanum 
8 
2-35 
386 
198 
0127 
6-4 
4th May 
Tilia 
60 
1*31 
344 
50 
0-053 
10-6 
12th May 
cordata 
60 
1-29 
463 
6-9 
0110 
16 0 
5th June 
6-0 
211 
421 
17*3 
0-123 
71 
Table XVIII. 
Assimilation Numbers of Autumn Leaves. 
Date. 
Species. 
Weight 
of Leaf 
gm. 
Dry 
Weight 
gm. 
Leaf 
Surface 
cm2. 
Chloro¬ 
phyll 
content 
mg. 
CO, 
ass. 
per. hr. 
gm. 
Ass. 
No. 
14th July 
Sambucus nigra 
8-0 
2-05 
359 
188 
0116 
6-2 
14th October 
Sambucus nigra 
(leaves easily 
detached) 
80 
1-64 
356 
8-2 
0 049 
60 
2nd November 
Populus pyramidalis 
(dark green leaves) 
80 
2-55 
376 
15 2 
0-152 
100 
2nd November 
Populus pyramidalis 
(yellow green leaves) 
80 
2-35 
363 
3-9 
0 031 
7-9 
In many cases, as will be seen from the next table, the 
assimilation number increases at the beginning of autumn and 
diminishes later. 
Table XIX. 
Assimilation Numbers of the Same Species at 
different times in Autumn. 
Date. 
Appearance 
of Leaf. 
Weight 
of Leaf 
gm. 
Dry 
Weight 
gm. 
Leaf 
Surface 
cm2. 
Chloro¬ 
phyll 
content 
mg. 
CO, 
ass. 
per hr. 
Ass. 
No. 
30th July 
deep green 
thin 
40 
1-55 
271 
19-7 
0-080 
4-1 
17th September 
green 
4-0 
1-55 
336 
12-5 
— 
6-6 
5th October ... 
green with 
yellow spots 
4-0 
1*45 
344 
78 
0-064 
8-5 
19th October ... 
almost yellow 
40 
1-35 
337 
2-1 
0-010 
4-8 
