later, i.e., at 6-50 a. m. The temperature, after reaching
Fig. 7. Diurnal curve of movement of procumbent young stem of Mimosa pudica. Successive dots at intervals of 15 minutes.
the maximum, began to fall at 12-25 p. m., and the previous movement of fall of the stem was arrested and reversed into an erectile movement shortly after 1 p. m. There are thus two "turning points," one at 7 a.m., and the other at about 1 p.m.; at these periods the movement of the plant remains more or less arrested for more than half-an-hour.
I obtained records of similar diurnal movements with various procumbent or creeping stems. Figure 7 gives the diurnal record of the procumbent stem of a young specimen of Mimosa pudica.
The experiment that has just been described shows clearly that geotropic curvatures of stems is opposed, or neutralised to a greater or less extent, during rise of temperature, and this antagonistic reaction is removed during the fall of temperature. The diurnal movement of the
