io8 



NATURE OF TENDRILS 



acts like a spring permitting considerable disturbance of the 

 vine without danger of breaking. This same device is copied 

 in making the attachment of the wires to the telephones and 

 other pieces of apparatus. From many standpoints the tendril 

 bearing stem is an admirable one. It is evident that such stems 

 can reach the light more directly and economically than twiners. 

 This doubtless accounts for their greater abundance and common 



Fig. 68. Fig. 69. 



Fig. 68. Tendrils of the bur cucumber: A, hooked tendrils in receptive 

 state. B, apical portion of tendril coiled about a branch and the remaining 

 portion of the tendril forming reversed coils, thus drawing the vine to the 

 supporting branch. — H. O. Hanson. 



Fig. 69. Branch of Japanese ivy attached to wall by means of tendrils 

 with adhesive discs. — J. O. Hanson. 



occurrence. It is also important to note that the tendrils are 

 especially abundant at the end of the branches where they reach 

 out considerably beyond the young leaves. Owing to the sway- 

 ing of the long free shoot of the climber in the wind and the 

 nutations of the tendril and shoot these sensitive organs are 



