OF MOVEMENT IN PLANTS. 65 
RELATION OF TEMPERATURE TO Rarp or Movement. 
(Deg. C. Distances in cm.) 

Means. 
U6 2: 3 A Das 050, c 1160, D. |) dae, | abs 8a. 8b. Sc. GE 

Average rate per | | 
minute.. .... 0.54 | 0.36 | 0.520} 0.140) 0.39 | 0.870; 0.290) 0.380! 0.205) 0.516) 0.483) 0.176) 0.191, 0.304 
Max. rate of | | 
movement. ..| 2.06 | 1.76 | 3.550) 0.850) 1.44 | 4.550) 6.500) 0.920) 0.555) 1.200! 2.600) 0.650! 2.170) 2.216 
Temp. for max. | | | | 
Hope one 28.30 [26.10 |27.800/35.500/27.20 |30.900/24.400/29. 00020. 00031. 700/22 .200/20.500/21. 10026 .500 
Minute rate of| | | 
movement. ..| 0.21 | 0.18 | 0.013] 0.031) 0.13 | 0.043) 0.047) 0.053) 0.080) 0.166) 0.100) 0.023) 0.020 0.084 
Temp. for min. | | | 
ratO ere 31.10 |31.70 |29.500/32.20021.70 |16.700/21.100/31 .100/22.800 34 .0024.000/19.500/20.000/27 .300 
















If we examine these results in their relation to the external conditions of growth, 
then we find that, of the thirteen observations given, only four show waves of rapid 
movement during the morning, these occurring between the hours of 7 and 10.20, and in 
no case—unless we except No. 9—representing the absolute maximum of motion for the whole 
life of the tendril. The remaining nine show the waves to occur in the afternoon, from 1.50 
to 7.12 o’clock. If, moreover, we select those figures which represent the true maximum 
of motion for the entire period of activity in each tendril, we shall find that only one such 
occurred in the morning, all the others taking place in the afternoon, between the hours 
of 1.50 and 6.50. 
Equalizing the hours of day and night, making the time of division 7 a.m. and 7 
p-m., we find the total length of diurnal movement to be 1359.90 cm.; and of nocturnal 
movement to be 536.90 em.; thus making the latter in the ratio of 1 : 2,53 to the former, 
a difference which clearly indicates that temperature exerts an influence which far 
outweighs any retarding effect due to the greater influence of sunlight. 
This naturally raises a question relative to the temperature under which these 
maxima were obtained. The values for tendrils 1, 3,5 b, c, 6a, 6, 86, and 9, the six highest 
rates observed, were obtained when the temperature ranged from 21.1° C. to 30.9°. Of 
these, the highest rates, viz., 6.50, 4.55, and 3.55, were obtained when the thermometer 
ranged from 24.4° C. to 30.9°; the other three giving values of 2.17, 2.60 and 2.06, were 
obtained between 21.1° C. and 28.3°. We thus find that the more active of these waves 
were formed under the influence of a temperature 3.8° C. higher than that under which 
the less active were produced. Again, taking the highest rate of each tendril movement 
—including those just given—we find them obtained under an average temperature of 
27.2° C.: while the waves of rapid movement in the same tendrils, but of less amplitude, 
were propagated under an average temperature of 24.8° C. Of the thirteen maxima of 
movement obtained, one was found to be coincident with the absolute maximum of 
temperature. This, however, was a movement at the low rate of 0.85 cm. per minute. 
Three were found to occur on an increasing temperature, usually several hours before the 
maximum was reached; and nine were observed on a descending temperature, from two 
to six hours after the maximum for the day had passed. 
Passing to the condition of the atmosphere in other respects, we find that the 
maximum movements in tendrils 1, 8b, 8c and 9 were reached under conditions of great 
Sec. IV., 1886. 9. 
