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answered in other plants, as the vine, Virginian creeper, and 
passion-flower, by tendrils ; and the phenomena of spontaneous 
motion in tendrils, are, if possible, still more curious. Some 
tendrils display the same power of rotatory motion possessed by 
the extremities of the shoots of climbing plants, others do not 
revolve, but are sensitive, bending to the touch. The curling 
movement consequent on a single touch continues to increase 
for a considerable time, then ceases ; after a few hours the 
tendril uncurls itself, and is again ready for action. A tendril 
will thus show a tendency to curl round any object with which 
it comes into contact, with the singular exception that it will 
seldom twine itself round another tendril of the same plant. It 
is also very curious that with some exceedingly sensitive plants, 
the falling of drops of rain on the tendril will produce no effect 
whatever. The mode in which a tendril of a Bignonia catches 
hold of a support is thus described by Darwin : — 44 The 
main petiole is sensitive to contact with any object ; even a 
small loop of thread after two days caused one to bend upwards. 
The whole tendrils are likewise sensitive to contact. Hence, 
when a shoot grows through branched twigs, its revolving move- 
ment soon brings the tendril into contact with some twig, and 
then all three 44 toes ” bend, (or sometimes one alone) and, after 
several hours, seize fast hold of the twig, exactly like a bird 
when perched.” The Virginian creeper has another mode of 
attaching itself to a wall or other solid support, by the forma- 
tion at the extremities of the branches of the tendril, of little 
disks or cushions, very similar to the disks on the foot of the 
house-fly by which it is enabled to attach itself to our windows 
and to walk along the ceiling. These disks secrete a glutinous 
fluid which attaches the tendril to the support with such strength 
that it is often impossible to detach it without destroying the 
tendril or even removing a portion of the wall itself. As soon 
as the attachment is accomplished the tendril gradually thickens 
and contracts spirally, as shown in Fig. 3, a, b. This spiral 
contraction, indeed, is always the result of the tendril meeting 
with a support ; and if no support is found, the tendril soon 
shrinks and withers away. Some tendrils exhibit a most re- 
markable power of selection, which, to use Mr. Darwin’s words, 
44 would, in an animal, be called instinct.” The tendrils of a 
species of Bignonia slowly travelled over the surface of a piece 
of wood, and when the apex of one of them came to a hole or 
fissure, it inserted itself ; the same tendril would frequently 
withdraw from one hole and insert its point into a second one. 
Mr. Darwin has seen a tendril keep its point, in one instance for 
twenty hours, and in another instance for thirty-six hours, in a 
minute hole, and then withdraw it. After the record of this 
fact on such unexceptional evidence, we are the more prepared 
