24 PLANT RESPONSE 



other words, the excitation travelled the intervening distance 

 with a speed of 2-3 mm. per second. The abnormal erectile 



Fig. 17. Response of Biophytum to Thermal Stimulation 



Stimulus was applied at some distance from the responding leaflet. 

 Thick dot represents moment of application oi stimulus. 



Fig. 18. Response of Biophytum to Electric Stimulation 

 Stimulus was applied directly on the pulvinus. Ordinate represents absolute 



movement in mm. 



effect, however — due, as will be explained later, to hydrostatic 

 disturbance — took place almost instantaneously. 



