81 
ponds to the iodine reaction, which was undertaken at the 
same time. The following figures represent the increase of 
weight in Connarus falcatus. 
Morning hours (bright weather) 7.5—10.50. . . . 1.04 gr. 
Afternoon hours (bright weather) 12.35—3.40. . . 0.55 gr. 
Morning hours (now and then clouded) 6.4512. . 0.41 gr. 
j » (between 10: and 12 cloudy) 6.40—12.10 0.16 gr. 
Afternoon hours (sky getting gradually clouded) 12.5—3.40 0 gr. 
Connarus macrophyllus. 
Afternoon hours (bright weather) 2.10—2.35 . . . 0.40 gr. 
Erythroxylon Coca. 
Morning hours (bright weather) 6.58—12. . . . . 0.40 gr. 
In order to facilitate comparison, I copy the figures arrived 
at by Sachs. 
Helianthus annuus. 
From 5 a. m. till 3 p.m. (sunny). . - ... . . 0.914 gr. 
Cucurbita Pepo. 
From 9 a. m. till noon (sunny). . pos a OS ert 
Rheum dificinals. 
From 6 a. m. till 11 a. m. (sunny). . a ee ci OBS. pie 
Pfeffer +) found for Phaseolus desieitonts 0.34 gr. per hour 
and M.? and for Helianthus 0.56 gr., but it should be noticed 
that the plants tested were cultivated in a greenhouse and 
moreover in pots. 
From the above results as to the colour of the leaves after 
immersion in iodine and from the figures arrived at, we are 
justified in concluding that herbs and small shrubs attain their 
maximum at 5 p.m. or maintain the same after twelve o’clock; 
that on the other hand trees and climbing or espalier plants 
lose part of their store after twelve o’clock. That the increase 
of organic matter in all plants is more energetic before twelve 
compared with later on, seems to me beyond question, the 
blue colour of leaves, treated with iodine being already very 
dark by this time. 
1) Pflanzenphysiologie hd 204. 
Aun. Jard. Buit. Vol. : 
