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Darwin, Charles, 1809-1882

"The Movements and Habits of Climbing Plants"

The embedded fibres are so closely clasped that they
cannot be withdrawn. The outgrowing tissue has so strong a tendency
to unite, that two balls produced by distinct tendrils sometimes
unite and grow into a single one.
On one occasion, when a tendril had curled round a stick, half an
inch in diameter, an adhesive disc was formed; but this does not
generally occur in the case of smooth sticks or posts. If, however,
the tip catches a minute projecting point, the other branches form
discs, especially if they find crevices to crawl into. The tendrils
failed to attach themselves to a brick wall.
I infer from the adherence of the fibres to the discs or balls, that
these secrete some resinous adhesive matter; and more especially from
such fibres becoming loose if immersed in sulphuric ether. This
fluid likewise removes small, brown, glistening points which can
generally be seen on the surfaces of the older discs. If the hooked
extremities of the tendrils do not touch anything, discs, as far as I
have seen, are never formed; {26} but temporary contact during a
moderate time suffices to cause their development. I have seen eight
discs formed on the same tendril.


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