The difference in the result in these two classes of cases, may perhaps
be accounted for by the matter saved through the abortion of the male organs in
the females of gyno-dioecious and dioecious plants being directed (as we shall
see in a future chapter) to the formation of an increased supply of seeds;
whilst in the case of the exterior florets and flowers of the plants which we
are here considering, such matter is expended in the development of a
conspicuous corolla. Whether in the present class of cases the corolla was first
affected, as seems to me the more probable view, or the reproductive organs
first failed, their states of development are now firmly correlated. We see this
well-illustrated in Hydrangea and Viburnum; for when these plants are
cultivated, the corollas of both the interior and exterior flowers become
largely developed, and their reproductive organs are aborted.
There is a closely analogous subdivision of plants, including the genus Muscari
(or Feather Hyacinth) and the allied Bellevalia, which bear both perfect flowers
and closed bud-like bodies that never expand. The latter resemble in this
respect cleistogamic flowers, but differ widely from them in being sterile and
conspicuous. Not only the aborted flower-buds and their peduncles (which are
elongated apparently through the principle of compensation) are brightly
coloured, but so is the upper part of the spike--all, no doubt, for the sake of
guiding insects to the inconspicuous perfect flowers.
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