ON DROSERA ROTUNDIFOLIA 11 
heavy line; the growth of the adaxial side is shown by the light 
line. The calculated growth of the median section of the tentacle 
is given by the broken line. The time is plotted on the abscissae; 
each space is thirty minutes. The changes in length are plotted 
on the ordinates; each space represents 0.02 mm. The reaction 
time is not indicated. The cross shows when the bending was 
completed and when unbending began. It is evident from the 
figure that the inflexion of the tentacle is produced by a con- 
siderable acceleration of the rate of growth on the abaxial side 
and in the median section. The unbending is more gradual and 
takes six times as long as the bending. Moreover the unbending 
is produced by a similar but less intense acceleration of the growth 
on the adaxial side and in the median section together with 
contraction of the abaxial side during the beginning of the process. 
The reaction of another tentacle is shown in TABLE II and Fic. 
TABLE II 
| No. of | to.16 | 10. 11,18 | 12.28 | 11.31 | 11.36 | x2. 12.38 | 58 | 9-45 
Sepment| A’'M.| Ac M,| A. M.|A.M,|A.M.| A. M.| P. M.| P, M.| P.M. A.M, 
72 | 72 72 72 "2 72 72 72 72 72 
118 | 118 | 118 | 118 | 118 | 118 | 119 | II9O | IO | TIO 
eG 39 Pah a8 att 338: 33) 34 | OF 34 
54 54 54 58 58 58 58 59 59 58 
| Total | 270 | 271 | 272 276 | 279 | 280 | 282 | 284 | 286 | 283 
- I 72 72 42 2 VER 72 
B Ao 2 21 {21 | I2t I2t I2t I2t I20 I20 120 I2f, 
5% a bas) a8 )35 |° 35 5°35) 635 | 35) 34} 33.4 43 
sn 4 |) 38 a7 | 37 5 37] 36): 35} 35] 34) 34) 42 
| Total | 266 | 265 | 265 | 265 | 264 | 263 | 262 | 260 | 259 | 278 
i} 
' 
gal 
| 
a a 
See 
Se bs 5 Se Se a 
SS ee ee a 
Fic. 5. A graph representing the bending and unbending of a tentacle, drawn 
according to data in TaBLE II, and on the same scale as Fic. 4. 
