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Darwin, Charles, 1809-1882

"The Different Forms of Flowers on Plants of the Same Species"

Moreover the seeds in the
same capsule frequently differ so much in size that it is scarcely possible to
decide which ought to be counted as good seed. There remains as the best
standard of comparison the proportional number of fertilised flowers which
produce capsules containing any seed.
First, for the one illegitimate short-styled plant. In the course of three
seasons 27 flowers were illegitimately fertilised with pollen from the same
plant, and they yielded only a single capsule, which, however, contained a
rather large number of seeds for a union of this nature, namely, 23. As a
standard of comparison I may state that during the same three seasons 44 flowers
borne by legitimate short-styled plants were self-fertilised, and yielded 26
capsules; so that the fact of the 27 flowers on the illegitimate plant having
produced only one capsule proves how sterile it was. To show that the conditions
of life were favourable, I will add that numerous plants of this and other
species of Primula all produced an abundance of capsules whilst growing close by
in the same soil with the present and following plants. The sterility of the
above illegitimate short-styled plant depended on both the male and female
organs being in a deteriorated condition. This was manifestly the case with the
pollen; for many of the anthers were shrivelled or contabescent.


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