)
I covered a plant growing in its native soil in North Wales with a net,
and fertilised six flowers each with its own pollen, and six others with
pollen from a distinct plant growing within the distance of a few feet.
The covered plant was occasionally shaken with violence, so as to
imitate the effects of a gale of wind, and thus to facilitate as far as
possible self-fertilisation. It bore ninety-two flowers (besides the
dozen artificially fertilised), and of these only twenty-four produced
capsules; whereas almost all the flowers on the surrounding uncovered
plants were fruitful. Of the twenty-four spontaneously self-fertilised
capsules, only two contained their full complement of seed; six
contained a moderate supply; and the remaining sixteen extremely few
seeds. A little pollen adhering to the anthers after they had dehisced,
and accidentally falling on the stigma when mature, must have been the
means by which the above twenty-four flowers were partially
self-fertilised; for the margins of the corolla in withering do not curl
inwards, nor do the flowers in dropping off turn round on their axes, so
as to bring the pollen-covered hairs, with which the lower surface is
clothed, into contact with the stigma--by either of which means
self-fertilisation might be effected.
Seeds from the above crossed and self-fertilised capsules, after
germinating on bare sand, were planted in pairs on the opposite sides of
five moderately-sized pots, which were kept in the greenhouse.
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