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any object, it contracts spirally. The revolving movement of 
the internodes is extremely slight. 
The diagram of the flowers of the vine (PI. VI., fig. 8) will 
show that the tendril here described is a modified flower 
peduncle. 
The two branches above mentioned correspond to B and C 
(as lettered in the figures), only here the longer (with the 
bract) bends downwards, evidently to give extra support to 
the bunch of grapes, which is formed upon what is homologi- 
cally the other branch of the tendril. 
The peduncle, c, increases in length, and loses its sensitive- 
ness in an inverse degree to the number of flower-buds. 
Thus, the fewer there are, the greater the length of the 
peduncle, and the more nearly does it assume the character of 
a tendril. 
Similarly, the “ flower-tendril,” b, occasionally bears flowers, 
and then “ in this state they retain their characteristic quali- 
ties of sensitiveness and spontaneous movement, but in a 
somewhat lessened degree.” In fact, a perfect gradation may 
be seen from the ordinary state of a “ flower-peduncle ” to 
that of a true tendril. Mr. Darwin remarks that this affords 
a good instance of the law of compensation. 
Amjpelopsis hederacea, or Virginian Creeper. — PI. VI., fig. 9, 
will illustrate the appearance of the tendril. There is but 
feeble sensitiveness in the branches, which turn from the light, 
as their purpose is not to climb by twining round objects, but 
by means of discs on flat surfaces, as follows : — When they 
meet a wall they all turn their branches towards it and bring 
the hooked tips laterally in contact with it. After arranging 
the branches satisfactorily, the curved tips swell, become bright 
red, and form on their under side little disks or cushions which 
apparently secrete some resinous fluid, and so assist in ad- 
hering the tendril firmly to the surface, for “ the cellular out- 
growth of the disk completely envelops every minute and 
irregular projection, and insinuates itself into every crevice.” 
An attached tendril increases in size, contracts spirally, and 
becomes highly elastic ; and even when subsequently dead, 
retains its strength and elasticity. 
Mr. Darwin mentions one branchlet which had been attached 
for ten years, yet supported a weight of two pounds. If any 
entire tendril, or branch of a tendril, do not attach itself, it 
shrivels up, and very soon drops off (see PI. VI., fig. 10). 
Our author concludes Part III., on Tendril-bearers, by several 
interesting remarks upon the Spiral contraction of Tendrils. 
This movement begins in half-a-day or a day or two after 
the extremities have caught some object. It occurs in all 
tendrils after seizure, with the principal exception of Corydalis 
