PLANT RESPONSE 



57 



fatigue was present. It will be seen that the curves 

 obtained by joining the apices of the successive single 

 responses are very similar. 



In one case there is no fatigue, the recovery from 

 each stimulus being complete. Every response in the 



30 



30 35 



20 



FIG. 34. KESPONSES TO INCREASING STIMULUS OBTAINED WITH Two SPECI- 

 MENS OF STALK OF CAULIFLOWER 



In (a) fatigue is absent, in (6) it is present. 



series therefore starts from a position of perfect equi- 

 librium, and the height of the single responses increases 

 with increasing stimulation. But in the second case, 



