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Darwin, Charles, 1809-1882

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

Some few
experiments were tried in 1863. The summer of 1864 was too hot and dry, and,
though the plants were copiously watered, some few apparently suffered in their
fertility, whilst others were not in the least affected. The years 1865 and,
especially, 1866, were highly favourable. Only a few observations were made
during 1867. The results are arranged in classes according to the parentage of
the plants. In each case the average number of seeds per capsule is given,
generally taken from ten capsules, which, according to my experience, is a
nearly sufficient number. The maximum number of seeds in any one capsule is also
given; and this is a useful point of comparison with the normal standard--that
is, with the number of seeds produced by legitimate plants legitimately
fertilised. I will give likewise in each case the minimum number. When the
maximum and minimum differ greatly, if no remark is made on the subject, it may
be understood that the extremes are so closely connected by intermediate figures
that the average is a fair one. Large capsules were always selected for
counting, in order to avoid over-estimating the infertility of the several
illegitimate plants.
In order to judge of the degree of inferiority in fertility of the several
illegitimate plants, the following statement of the average and of the maximum
number of seeds produced by ordinary or legitimate plants, when legitimately
fertilised, some artificially and some naturally, will serve as a standard of
comparison, and may in each case be referred to.


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