Tendrils of both
kinds spontaneously revolve at about the same rate. Both, when
touched, bend quickly to the touched side, and afterwards recover
themselves and are able to act again. In both the sensitiveness is
either confined to one side or extends all round the tendril. Both
are either attracted or repelled by the light. The latter property
is seen in the foliar tendrils of Bignonia capreolata and in the
axial tendrils of Ampelopsis. The tips of the tendrils in these two
plants become, after contact, enlarged into discs, which are at first
adhesive by the secretion of some cement. Tendrils of both kinds,
soon after grasping a support, contract spirally; they then increase
greatly in thickness and strength. When we add to these several
points of identity the fact that the petiole of Solanum jasminoides,
after it has clasped a support, assumes one of the most
characteristic features of the axis, namely, a closed ring of woody
vessels, we can hardly avoid asking, whether the difference between
foliar and axial organs can be of so fundamental a nature as is
generally supposed? {46}
We have attempted to trace some of the stages in the genesis of
climbing plants.
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