It is a far more remarkable
fact--if we bear in mind the effects of crossing plants with pollen from
a fresh stock in the cases of Ipomoea, Mimulus, Brassica, and
Iberis--that the self-fertilised plants exceeded in height (as 109 to
100), and in weight (as 118 to 100), the offspring of the Brazilian
stock crossed by the English stock; the two stocks having been long
subjected to widely different conditions.
If we now turn to the fertility of the three lots of plants we find a
very different result. I may premise that in five out of the nine pots
the first plant which flowered was one of the English-crossed; in four
of the pots it was a self-fertilised plant; and in not one did an
intercrossed plant flower first; so that these latter plants were beaten
in this respect, as in so many other ways. The three closely adjoining
rows of plants growing in the open ground flowered profusely, and the
flowers were incessantly visited by bees, and certainly thus
intercrossed. The manner in which several plants in the previous
experiments continued to be almost sterile as long as they were covered
by a net, but set a multitude of capsules immediately that they were
uncovered, proves how effectually the bees carry pollen from plant to
plant. My gardener gathered, at three successive times, an equal number
of ripe capsules from the plants of the three lots, until he had
collected forty-five from each lot.
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