It is not possible to judge from
external appearance whether or not a capsule contains any good seeds; so
that I opened all the capsules. Of the forty-five from the
English-crossed plants, four were empty; of those from the intercrossed,
five were empty; and of those from the self-fertilised, nine were empty.
The seeds were counted in twenty-one capsules taken by chance out of
each lot, and the average number of seeds in the capsules from the
English-crossed plants was 67; from the intercrossed, 56; and from the
self-fertilised, 48.52. It therefore follows that:--
The forty-five capsules (the four empty ones included) from the
English-crossed plants contained 2747 seeds.
The forty-five capsules (the five empty ones included) from the
intercrossed plants contained 2240 seeds.
The forty-five capsules (the nine empty ones included) from the
self-fertilised plants contained 1746.7 seeds.
The reader should remember that these capsules are the product of
cross-fertilisation, effected by the bees; and that the difference in
the number of the contained seeds must depend on the constitution of the
plants;--that is, on whether they were derived from a cross with a
distinct stock, or from a cross between plants of the same stock, or
from self-fertilisation. From the above facts we obtain the following
ratios:--
Number of seeds contained in an equal number of naturally fertilised
capsules produced:--
By the English-crossed and self-fertilised plants, as 100 to 63.
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