I have no doubt, from
the analogy of the two following allied species, that the petioles
also move spontaneously; but they are not irritable like those of B.
unguis and B. Tweedyana. The young internodes sweep large circles,
one being completed in 2 hrs. 15 m., and a second in 2 hrs. 55 m. By
these combined movements of the internodes, petioles, and grapnel-
like tendrils, the latter are soon brought into contact with
surrounding objects. When a shoot stands near an upright stick, it
twines regularly and spirally round it. As it ascends, it seizes the
stick with one of its tendrils, and, if the stick be thin, the right-
and left-hand tendrils are alternately used. This alternation
follows from the stem necessarily taking one twist round its own axis
for each completed circle.
The tendrils contract spirally a short time after catching any
object; those which catch nothing merely bend slowly downwards. But
the whole subject of the spiral contraction of tendrils will be
discussed after all the tendril-bearing species have been described.
Bignonia littoralis.--The young internodes revolve in large ellipses.
An internode bearing immature tendrils made two revolutions, each in
3 hrs.
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