Cucurbita maxima and C. Pepo. 101 



following the greatest heat wave. The waves of slowest mo- 

 tion covered the time from 10 A. M. to 2.30 P. M., coincident 

 with a rising temperature. The absolute minimum of motion 

 occurred just before the maximum of temperature and was at 

 the rate of 0"21. om per minute. At 4 o'clock in the morning, a 

 heavy rain ceased. The air was still surcharged with moisture, 

 and the sky was entirely overcast with heavy clouds. It was 

 while this condition lasted that the waves of slowest motion 

 occurred, the minimum being found during the interval from 

 12.15 to 1 P. M. At the latter hour the clouds broke and the 

 sun came out brightly and so continued until 6 P. M., when the 

 sky again became overcast and rain set in at 7 o'clock. While 

 the sun was out, the tendril was most active, absolute maxi- 

 mum of movement taking place in the five minutes from 3.25 

 to 3.30 P. M., the whole distance traveled in that time being 

 16-30 cm . 



The first direction of movement was to the right. This, 

 however, was obviously purely accidental, since the direction 

 first recorded must depend upon the time of first observation, 

 dextrorse alternating with sinistrorse action during the whole 

 movement of the tendril. The entire motion to the right 

 amounted to 190-8 cm ; that to the left reached a total of 152-35 cm ; 

 the ratio of the one to the other thus being as 1 : 0*79. 



Tendril JVo. 2. 



The second tendril was selected on the 13th of August, at 8 

 o'clock a. M. It was a shorter arm than No. 1, and rather 

 nearer the end of its activity. The time of movement was 

 six hours and fifteen minutes, and the entire distance traveled 

 was 136'00 cm , thus giving an average rate per minute of 0*36 om . 



The absolute maximum of movement was l - 76 cm per minute 

 and occurred from 10.15 to 10.20 A. M., forty -five minutes be- 

 fore the maximum temperature for the day was reached. The 

 waves of most rapid movement covered the time between 8 

 and 10.50 A. M., coincident with increasing temperature. The 

 waves of least motion occurred between 10.50 a. m. and 2 

 P. M., during a slight depression of temperature. The abso- 

 lute minimum was reached between 10.50 and 12.15 M.., and 

 amounted to OlYO 0111 . It directly succeeded the maximum of 

 temperature. During the entire time of observation, the weather 

 was very pleasant, though somewhat cloudy. At twelve 

 o'clock, the leaves began to droop from the effects of excessive 

 transpiration and heat. This continued until after the close of 

 observation. It was during this time of depressed activity and 

 reduced tension, that the minimum of motion occurred. Dur- 

 ing the entire morning, all the leaves and flowers showed great 

 vigor, and it was while in this condition that most active move- 



