88 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



and the leaves developed to the normal length. The inflorescence 

 remained in the form of a slender bud with a scape about 3 cm. long. 

 The outer leaf was attached to a precision auxanometer in such 

 manner that the nutations of the tip were prevented and a complete 

 continuous record for the entire period of growth was obtained, during 

 a period of about fifty days. A study of this curve fails to reveal any 

 regular rhythmic action. Elongation varied from the average rate 





Fig. 44. Precision auxanometer used in measuring growth of leaf of ^uamasia 

 The instrument is shown with the lever attached to a leaf of Hyacint/ius, and is adjusted 

 to magnify the elongation fortv-five times. (For full description of construction and 

 use see MacDougal's Practical Text Book of Plant Physiology, pp. 291, 292. 1901.) 



above and below it at times, but such fluctuations were doubtless due 

 in part to the application of water to the cultures which was done at 

 various times of the day, whenever necessar3^ The temperature was 

 constant to within 3° C. as described above. (See Fig. 45.) 



Canna (cultivated). 



Rootstocks of Canna placed in the dark room soon began to send 



up a succession of leaves, which reached a maximum length of 45 



cm. and which had a lamina more attenuated than the normal, being 



about 40 cm. long, and only 8 cm. in width. Such alterations from 



