In each generation, also,
the crossed plants were fertilised with pollen from another crossed
plant.
Of the flowers which were crossed in the three generations, taken
together, a rather larger proportion yielded capsules than did those
which were self-fertilised. The seeds were counted in forty-seven
capsules from the crossed flowers, and they contained on an average 9.95
seeds; whereas forty-eight capsules from the self-fertilised flowers
contained on an average 8.45 seeds; or as 100 to 85. The seeds from the
crossed flowers were not heavier, on the contrary a little lighter, than
those from the self-fertilised flowers, as was thrice ascertained. On
one occasion I weighed 200 of the crossed and 106 of the self-fertilised
seeds, and the relative weight of an equal number was as 100 for the
crossed to 101.5 for the self-fertilised. With other plants, when the
seeds from the self-fertilised flowers were heavier than those from the
crossed flowers, this appeared to be due generally to fewer having been
produced by the self-fertilised flowers, and to their having been in
consequence better nourished. But in the present instance the seeds from
the crossed capsules were separated into two lots,--namely, those from
the capsules containing over fourteen seeds, and those from the capsules
containing under fourteen seeds, and the seeds from the more productive
capsules were the heavier of the two; so that the above explanation here
fails.
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