That is, the growth is so great along one side that it
bends the shoot completely over to the opposite side, thus forming a hook;
the longitudinal line or zone of growth then travels a little laterally
round the shoot, and the hook points in a slightly different direction, and
so onwards until the hook is completely reversed. Ultimately it
* 'The Movements and Habits of Climbing Plants,' 2nd edit. p. 13.
[page 272]
comes back to the point whence it started. This was ascertained by painting
narrow lines with Indian ink along the convex surface of several hooks, and
the line was found slowly to become at first lateral, then to appear along
the concave surface, and ultimately back again on the convex surface. In
the case of Lonicera brachypoda the hooked terminal part of the revolving
shoot straightens itself periodically, but is never reversed; that is, the
periodically increased growth of the concave side of the hook is sufficient
only to straighten it, and not to bend it over to the opposite side. The
hooking of the tip is of service to twining plants by aiding them to catch
hold of a support, and afterwards by enabling this part to embrace the
support much more closely than it could otherwise have done at first, thus
preventing it, as we often observed, from being blown away by a strong
wind.
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