The closed and
imperfect flowers are, however, manifestly of high importance, as they
yield with the utmost safety a large stock of seed, with the expenditure of
wonderfully little pollen. The two kinds of flowers often differ much, as
just stated, in structure. The petals in the imperfect flowers almost
always consist of mere rudiments, and the pollen-grains are reduced in
diameter. In Ononis columnae five of the alternate stamens are
rudimentary; and in some species of Viola three stamens are in this state,
two retaining their proper function, but being of very small size. In six
out of thirty of the closed flowers in an Indian violet (name unknown, for
the plants have never produced with me perfect flowers), the sepals are
reduced from the normal number of five to three. In one section of the
Malpighiaceae the closed flowers, according to A. de Jussieu, are still
further modified, for the five stamens which stand opposite to the sepals
are all aborted, a sixth stamen standing opposite to a petal being alone
developed; and this stamen is not present in the ordinary flowers of this
species; the style is aborted; and the ovaria are reduced from three to
two. Now although natural selection may well have had the power to prevent
some of the flowers from expanding, and to reduce the amount of pollen,
when rendered by the closure of the flowers superfluous, yet hardly any of
the above special modifications can have been thus determined, but must
have followed from the laws of growth, including the functional inactivity
of parts, during the progress of the reduction of the pollen and the
closure of the flowers.
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