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cause the stamens to spring forward, as
has shown to be the case with the barberry; and
in this very genus, which seems to have a special contrivance for self-fertilisation, it is well known
if
closely-allied forms or varieties are planted near each other, it is hardly possible to raise pure seedlings, so largely do they naturally cross. In
other cases, far from
being
→any aids for self-fertilisation,
there are special
→as
I could show from the
of
Sprengel and
→from
my own
→which effectually prevent the stigma receiving pollen from its own flower:
for instance, in Lobelia fulgens, there is a really beautiful and elaborate contrivance by which
→all
the infinitely numerous pollen-granules are swept out of the conjoined anthers of each flower, before the stigma of that individual flower is ready to receive them; and as this flower is never visited, at least in my garden, by insects, it never sets a seed, though by placing pollen from one flower on the stigma of another, I raised plenty of
↑
In very many other cases, though there
no special mechanical contrivance to prevent the stigma
→of a flower receiving its own pollen,
yet, as
→C. C. Sprengel has
shown, and as I can confirm, either the anthers burst before the stigma is ready for fertilisation, or the stigma is ready before the pollen of that flower is ready, so that these
→plants
have in fact separated sexes, and must habitually be crossed. So it is with the reciprocally dimorphic and trimorphic plants previously alluded to. How strange are these facts! How strange that the pollen and stigmatic surface of the same flower, though placed so close together, as if for the very purpose of self-fertilisation, should
→in so many cases be
mutually useless to each
How
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