The flower-stems also differ much in height; and a poor
plant will sometimes throw up a higher stem than that of a fine plant.
In the later experiments, the fully-grown plants were cut down and
weighed, and then the immense advantage from a cross became manifest.
A single plant of the above variety was covered with a net just before
flowering, and was crossed with pollen from another plant of the same
variety growing close by; and the seven capsules thus produced contained
on an average 16.3 seeds, with a maximum of twenty in one capsule. Some
flowers were artificially self-fertilised, but their capsules did not
contain so many seeds as those from flowers spontaneously
self-fertilised under the net, of which a considerable number were
produced. Fourteen of these latter capsules contained on an average 4.1
seeds, with a maximum in one of ten seeds; so that the seeds in the
crossed capsules were in number to those in the self-fertilised capsules
as 100 to 25. The self-fertilised seeds, fifty-eight of which weighed
3.88 grains, were, however, a little finer than those from the crossed
capsules, fifty-eight of which weighed 3.76 grains. When few seeds are
produced, these seem often to be better nourished and to be heavier than
when many are produced.
The two lots of seeds in an equal state of germination were planted,
some on opposite sides of a single pot, and some in the open ground.
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