movement which was only moderate in extent. But the Faridpur Palm growing at an inclination of 60° was subjected more effectively to geotropic action, and exhibited movements which were far more pronounced. I shall now proceed to describe crucial experiments which will demonstrate the effect of change of temperature on geotropic curvature.
EFFECT OF VARIATION OF TEMPERATURE ON GEOTROPIC CURVATURE.
In the instances of diurnal movement already described the trees or their leaves were already at an inclination to the vertical. I now took a radial and erect shoot of Basella cordifolia growing in a pot and laid it horizontally for two weeks. The procumbent stem curved up and attained a state of equilibrium under the action of geotropic stimulus.
Diurnal curve of Basella cordifolia: Experiment 7.— The plant was completely immersed in a vessel of water, and its diurnal curve recorded. This resembled in all essentials the diurnal curve of the Palm; the slight deviation was due to the fact that owing to difference in the season (August) the temperature maximum was attained at 12-25 p. m., and the minimum at 6 a. m. The geotropic curvature was reduced to its minimum at the maximum temperature, and vice versâ. As in the case of the Palm so also in the procumbent stem of Basella there was a physiological lag, which was 50 minutes in the morning and about the same in the afternoon. The free end of the stem thus exhibited a diurnal movement up and down. The temperature, as stated before, began to rise from 6 a. m. and the down-movement commenced 50 minutes
