Chap. IV. VITACE^. 149 



that when the main foot-stalk is pulled the strain is 

 distributed equally between all the attached discs. 

 For a few days after the attachment of the discs, the 

 tendril remains weak and brittle, but it rapidly increases 

 in thickness and acquires great strength. During the 

 following winter it ceases to live, but adheres firmly in 

 a dead state both to its own stem and to the surface of 

 attachment. In the accompanying diagram (fig. 11.) 

 we see the difference between a tendril (B) some weeks 

 after its attachment to a wall, with one (A) from the 

 same plant fully grown but unattached. That the 

 change in the nature of the tissues, as well as the 

 spiral contraction, are consequent on the formation of 

 the discs, is well shown by any lateral branches which 

 have not become attached ; for these in a week or two 

 wither and drop off, in the same manner as does the 

 whole tendril if unattached. The gain in strength 

 and durability in a tendril after its attachment is 

 something wonderful. There are tendrils now adhering 

 to my house which are still strong, and have been 

 exposed to the weather in a dead state for fourteen or 

 fifteen years. One single lateral branchlet of a tendril, 

 estimated to be at least ten years old, was still elastic 

 and supported a weight of exactly two pounds. The 

 whole tendril had five disc-bearing branches of equal 

 thickness and apparently of equal strength ; so that 

 after having been exposed during ten years to the 

 weather, it would probably have resisted a strain of 

 ten pounds ! 



SAriNDACE^:. Cardiospermum halicacalum. In this 



