Cucurbita maxima and C. Pepo. 109 



The greatest rate of movement was found to be 0'42 cm per 

 minute and occurred from 10.10 to 10.40 A. M. on a rising tem- 

 perature. The least movement was from 11.30 to 12 M., at the 

 rate of 0"013 cm per minute. 



During the time of observation, the temperature was quite 

 uniform, varying only three degrees. The sky was overcast 

 during the night and the air was loaded with moisture. At 

 5 a. M. there was a cold east wind, but this did not seem to in- 

 terfere with the activity of the plant. The closing observa- 

 tions were taken in a hard rain, which commenced at ten 

 o'clock. The entire dextrorse movement was 60 - 10 cm ; the 

 sinistrorse 36*80, and the ratio as 1 : - 61. The whole range of 

 vertical movement in which the effect of geotropism was very 

 evident, was 17'60 cm ; negative heliotropism (?) 16'90 cm ; posi- 

 tive heliotropism (?) 10"30 cm . 



Collateral to the observations concerning movements, it was 

 deemed wise to collect all other facts which, through any ex- 

 planation of the general phenomenon of growth they might 

 afford, would throw light upon the special question under con- 

 sideration. It was with this view that the following facts con- 

 cerning growth in both vine and fruit were collected. 



Growth of the vine. 



To determine the hourly growth of the vine, a board, suit- 

 ably marked off into a scale of inches and tenths, was placed 

 in a vertical position at one side of the growing extremity and 

 parallel with it. The scale was placed at one side rather than 

 beneath in order to avoid inaccuracy which might arise through 

 the vertical movement of the terminal bud, which would of 

 course, at times, bring it some distance from the scale. Read- 

 ings were taken every hour. Observations were continued for 

 158 hours, almost consecutively. The entire growth of the 

 vine during that time was 89*40 cm , giving an average hourly 

 growth of 0"566 om . The most rapid rate of growth was l - 015 cm 

 per hour. This rate was reached eight times out of the 158 

 and, with one exception, occurred at noon, between the hours 

 of 12 M. and 2 P. M. This rate was also obtained under the 

 influence of high temperature. 



The slowest rate of hourly growth was OO'OO™. This oc- 

 curred only once, at 8 o'clock P. M., and was due to no appar- 

 ent cause. Minimum movements of 0"253 cni frequently occurred 

 The waves of least movement were obtained at or soon after 

 midnight, consequently at a time of low temperature. 



The entire growth of the vine during the night was 34 # 287 cm .* 

 The entire growth during the day was 44 , 447 0m , and the ratio 



* All the observations are not included here, as some must of necessity be left 

 out to equalize hours of day and night. 



