(7/2. 'Transactions of the Linnean Society' volume 8
page 600.) It may also be worth while to recall the case of the mid-styled form
of Lythrum salicaria, which produces a larger number of seeds than the other
forms, and has somewhat smaller pollen-grains which have less fertilising power
than those of the corresponding stamens in the other two forms; but whether the
larger number of seeds is the indirect cause of the diminished power of the
pollen, or vice versa, I know not. As soon as the anthers in a certain number of
individuals became reduced in size in the manner just suggested or from any
other cause, the other individuals would have to produce a larger supply of
pollen; and such increased development would tend to reduce the female organs
through the law of compensation, so as ultimately to leave them in a rudimentary
condition; and the species would then become dioecious.
Instead of the first change occurring in the female organs we may suppose that
the male ones first varied, so that some individuals produced a larger supply of
pollen. This would be beneficial under certain circumstances, such as a change
in the nature of the insects which visited the flowers, or in their becoming
more anemophilous, for such plants require an enormous quantity of pollen. The
increased action of the male organs would tend to affect through compensation
the female organs of the same flower; and the final result would be that the
species would consist of males and hermaphrodites.
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