356), is the case with
all the internodes of a certain variety of Phaseolus multiflorus.
Internodes which have become twisted round their own axes, if they
have not ceased to revolve, are still capable of twining round a
support, as I have several times observed.
Mohl has remarked (p. 111) that when a stem twines round a smooth
cylindrical stick, it does not become twisted. {6} Accordingly I
allowed kidney-beans to run up stretched string, and up smooth rods
of iron and glass, one-third of an inch in diameter, and they became
twisted only in that degree which follows as a mechanical necessity
from the spiral winding. The stems, on the other hand, which had
ascended ordinary rough sticks were all more or less and generally
much twisted. The influence of the roughness of the support in
causing axial twisting was well seen in the stems which had twined up
the glass rods; for these rods were fixed into split sticks below,
and were secured above to cross sticks, and the stems in passing
these places became much twisted. As soon as the stems which had
ascended the iron rods reached the summit and became free, they also
became twisted; and this apparently occurred more quickly during
windy than during calm weather.
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