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Darwin, Charles, 1809-1882

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

First, an equal-styled plant, protected from
insects (as was done in all the following cases, with one stated exception),
spontaneously produced numerous capsules, five of which gave an average of 44.8
seeds, with a maximum in one capsule of 57. But six capsules, the product of
fertilisation with pollen from a short-styled cowslip (and this is a legitimate
union), gave an average of 28.5 seeds, with a maximum of 49; and this is a much
lower average than might have been expected. Secondly, nine capsules from
another equal-styled plant, which had not been protected from insects, but
probably was self-fertilised, gave an average of 45.2 seeds, with a maximum of
58. Thirdly, another plant which had a very short pistil in 1865, produced
spontaneously many capsules, six of which contained an average of 33.9 seeds,
with a maximum of 38. In 1866 this same plant had a pistil of wonderful length;
for it projected quite above the anthers, and the stigma resembled that of the
long-styled form. In this condition it produced spontaneously a vast number of
fine capsules, six of which contained almost exactly the same average number as
before, namely 34.3, with a maximum of 38. Four flowers on this plant,
legitimately fertilised with pollen from a short-styled cowslip, yielded
capsules with an average of 30.2 seeds. Fourthly another short-styled plant
spontaneously produced in 1865 an abundance of capsules, ten of which contained
an average of 35.


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