)
Anemophilous flowers resemble in many respects cleistogene flowers, but
differ widely in not being closed, in producing an extraordinary amount
of pollen which is always incoherent, and in the stigma often being
largely developed or plumose. We certainly owe the beauty and odour of
our flowers and the storage of a large supply of honey to the existence
of insects.
ON THE RELATION BETWEEN THE STRUCTURE AND CONSPICUOUSNESS OF FLOWERS,
THE VISITS OF INSECTS, AND THE ADVANTAGES OF CROSS-FERTILISATION.
It has already been shown that there is no close relation between the
number of seeds produced by flowers when crossed and self-fertilised,
and the degree to which their offspring are aaffected by the two
processes. I have also given reasons for believing that the inefficiency
of a plant's own pollen is in most cases an incidental result, or has
not been specially acquired for the sake of preventing
self-fertilisation. On the other hand, there can hardly be a doubt that
dichogamy, which prevails according to Hildebrand in the greater number
of species (10/23. 'Die Geschlecter Vertheiling' etc. page 32.),--that
the heterostyled condition of certain plants,--and that many mechanical
structures--have all been acquired so as both to check
self-fertilisation and to favour cross-fertilisation. The means for
favouring cross-fertilisation must have been acquired before those which
prevent self-fertilisation; as it would manifestly be injurious to a
plant that its stigma should fail to receive its own pollen, unless it
had already become well adapted for receiving pollen from another
individual.
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