Now if we suppose the tendrils of L.
aphaca to become flattened and foliaceous, like the little
rudimentary tendrils of the bean, and the large stipules to become at
the same time reduced in size, from not being any longer wanted, we
should have the exact counterpart of L. nissolia, and its curious
leaves are at once rendered intelligible to us.
It may be added, as serving to sum up the foregoing views on the
origin of tendril-bearing plants, that L. nissolia is probably
descended from a plant which was primordially a twiner; this then
became a leaf-climber, the leaves being afterwards converted by
degrees into tendrils, with the stipules greatly increased in size
through the law of compensation. {48} After a time the tendrils lost
their branches and became simple; they then lost their revolving-
power (in which state they would have resembled the tendrils of the
existing L. aphaca), and afterwards losing their prehensile power and
becoming foliaceous would no longer be thus designated. In this last
stage (that of the existing L. nissolia) the former tendrils would
reassume their original function of leaves, and the stipules which
were recently much developed being no longer wanted, would decrease
in size.
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