26 grains weight
of seed.
Ten intercrossed capsules would have contained 4.14 grains weight of
seed.
Ten self-fertilised capsules would have contained 3.00 grains weight of
seed.
We thus get the following ratios:--
Seeds from the Westerham-crossed capsules to those from the capsules of
the fifth self-fertilised generation, in weight as 100 to 48.
Seeds from the Westerham-crossed capsules to those from the capsules of
the fifth intercrossed generation, in weight as 100 to 66.
Seeds from the intercrossed capsules to those from the self-fertilised
capsules, in weight as 100 to 72.
So that a cross with pollen from a fresh stock greatly increased the
productiveness of the flowers on plants which had been self-fertilised
for the four previous generations, in comparison not only with the
flowers on the same plants self-fertilised for the fifth time, but with
the flowers on the crossed plants crossed with pollen from another plant
of the same old stock for the fifth time.
These three lots of seeds were placed on sand, and were planted in an
equal state of germination in seven pots, each made tripartite by three
superficial partitions. Some of the remaining seeds, whether or not in a
state of germination, were thickly sown in an eighth pot. The pots were
kept in the greenhouse, and the plants trained up sticks. They were
first measured to the tops of their stems when coming into flower; and
the twenty-two Westerham-crossed plants then averaged 25.
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