234 



CIRCUMNUTATION OF LEAVES. 



CHAP. IV. 



As the evening rise and the early morning fall were unusually 

 large, the angle of the petiole above the horizon was measured 

 at the two periods, and the leaf was found to have risen 19 



Fig. 100. 



Vicia faba: circumnutation of leaf, traced from 7.15 P.M. July 2nd to 

 10.15 A.M. 4th. Apex of the two terminal leaflets 7J inches from the 

 vertical ^lass. Figure here reduced to two-thirds of original scale. 

 Temp. 17-18 C. 



between 12.20 P.M. and 10.45 P.M., and to have fallen 23 30* 



between the latter hour and 10.20 A.M. on the following morning. 



The main petiole was now secured to a stick close to the base 



