108 D. P. Penhallow — Tendril Movements in 



3 P. M., at the rate per minute of 0*023 cm , occurring at the time 

 of minimum temperature. The extreme variation of tempera- 

 ture during the hours of observation, was only 2° C. A light 

 rain fell during the greater part of the time, and heavy clouds 

 obscured the sky the remainder. The movement to the right 

 was H7.60 cm ; to the left 41-40 cm , and the ratio therefore, as 

 1:0-35. 



Tendril No. 9. 



The last tendril experimented with was selected August 17th 

 at 6 o'clock P. m. It was in the last stages of movement, and 

 exhibited the least horizontal movements of any upon which 

 observations were taken. The whole length of movement was 

 191'30 cm ; the time sixteen hours and forty minutes, and the 

 consequent average rate per minute was 0"191 cm . 



The greatest movement was from 7 to 7.06 A. M., at the rate 

 of 2"17 om per minute. This occurred in a slightly increasing 

 temperature. The waves of most rapid movement were from 

 5 to 9 A. M. The least movement occurred from 9.30 to 10.00 

 P. M., at the average rate of 0'02 cm per minute. The waves of 

 slowest movement were found from 6 P. M. until 5 A. M. 



The temperature varied only three degrees during the entire 

 time of observation. From the commencement until 10 o'clock 

 P. M., light rain fell and the sky was entirely overcast until the 

 close of observations. At 5 A. M,, there was a cool east wind 

 with a very large amount of moisture in the air, and the plant 

 was apparently in a very active condition. At the close of 

 observation, heavy rain commenced to fall. The total dex- 

 trorse movement was lGO'^O 0111 ; the sinistrorse 30*9 cm ; and the 

 ratio as 1: 0\L81. 



Terminal Hud. 



For experiment, there was selected a good terminal bud 

 upon the extremity of a vigorous vine growing directly from 

 west to east. The observed movements were chiefly in verti- 

 cal direction, those in a horizontal plane being, apparently, not 

 so conspicuous. The total movement was 96"90 om at the aver- 

 age rate of 0'065 cm per minute, the observations extending 

 over fifteen hours and twenty-eight minutes. As might be 

 expected, this movement was much slower than that of the 

 tendrils, but at the same time, sufficiently rapid and continu- 

 ous in a given direction, to make the observations very easy. 

 In this circumnutation, geotropism and heliotropism exert an 

 important influence upon the figure described by the tip as the 

 result of growth. The end of the vine is constantly turned 

 upward, and during a certain time becomes more and more ele- 

 vated, finally falling back towards the ground. This is re- 

 peated continually during the entire growth of the vine, the 

 change usually taking place once each day. 



