As pollen is deposited at a very early age on the pistil, generally in
contact with the stigma, some flowers whilst still in bud were castrated
for my first experiment, and were afterwards fertilised with pollen from
a distinct plant. Other flowers were fertilised with their own pollen.
From the seeds thus obtained, I succeeded in rearing only three pairs of
plants of equal age. The three crossed plants averaged 32.79 inches, and
the three self-fertilised 32.08 inches in height; so that they were
nearly equal, the crossed having a slight advantage. As the same result
followed in all three generations, it would be superfluous to give the
heights of all the plants, and I will give only the averages.
In order to raise crossed and self-fertilised plants of the second
generation, some flowers on the above crossed plants were crossed within
twenty-four hours after they had expanded with pollen from a distinct
plant; and this interval would probably not be too great to allow of
cross-fertilisation being effectual. Some flowers on the self-fertilised
plants of the last generation were also self-fertilised. From these two
lots of seeds, ten crossed and twelve self-fertilised plants of equal
ages were raised; and these were measured when fully grown. The crossed
averaged 36.98, and the self-fertilised averaged 37.42 inches in height;
so that here again the two lots were nearly equal; but the
self-fertilised had a slight advantage.
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