370 The Botanical Gazette. [June, 
of temperature. The mean night growth of leaves III and IV 
was 1.25 inch, and the mean daily growth was 2.8 inch, which 
shows that about 70 per cent. of the total growth ‘took place 
during the day, between 7:30 A. M. and 5:30 P. M. It also 
illustrates the. éffect of length of day. 
The effect produced by variations of either day or night tem- 
peratures it is not easy to decide. In leaf I, for example, it is 
strongly indicated that the sudden and great fall of tempera- 
ture on Jan. 30th, continuing over Jan. 31st, caused a decrease 
in the growth of the leaf. In the other examples, such as 
IV, a small fallin the night temperature, as on March 4th, 
does not at all interfere with the maximum growth. From 
this it appears that a great lowering of the temperature is nec- 
essary to seriously arrest progressive growth. 
I am of opinion that the action of direct sunlight, and the 
direction and force of the wind, are more potent factors in 
increasing or arresting growth than small variations of tem- 
Benny On this subject I have, at present, no conclusive 
ata 
The banana is an excellent subject in which to study given 
features of physiological development. The growth of its 
leaves is so rapid that Measurements can be recorded twice 
daily with a measuring rule, and with the possibility of ex- 
tremely small error. This is of great value in affording light 
upon the laws and conditions affecting the growth of other 
plants. The Sugar cane, for example, grows so. comparatively 
plants. 
Hawaiian Experiment Station, Honolulu, H. I. 
