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Darwin, Charles, 1809-1882

"The Movements and Habits of Climbing Plants"

The tips and the inner surfaces
of the hooks now began to swell, and in two or three days were
visibly enlarged. After a few more days the hooks were converted
into whitish, irregular balls, rather above the 0.05th of an inch
(1.27 mm.) in diameter, formed of coarse cellular tissue, which
sometimes wholly enveloped and concealed the hooks themselves. The
surfaces of these balls secrete some viscid resinous matter, to which
the fibres of the flax, &c., adhere. When a fibre has become
fastened to the surface, the cellular tissue does not grow directly
beneath it, but continues to grow closely on each side; so that when
several adjoining fibres, though excessively thin, were caught, so
many crests of cellular matter, each not as thick as a human hair,
grew up between them, and these, arching over on both sides, adhered
firmly together. As the whole surface of the ball continues to grow,
fresh fibres adhere and are afterwards enveloped; so that I have seen
a little ball with between fifty and sixty fibres of flax crossing it
at various angles and all embedded more or less deeply. Every
gradation in the process could be followed--some fibres merely
sticking to the surface, others lying in more or less deep furrows,
or deeply embedded, or passing through the very centre of the
cellular ball.


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