On the contrary, the intercrossed plants
had certainly been crossed for the last ten generations, and probably,
during all previous generations, as we may infer from the structure of
the flowers and from the frequency of the visits of humble-bees. And so
it will have been with the parent-plants of the fresh stock. The whole
great difference in height and fertility between the two lots must be
attributed to the one being the product of a cross with pollen from a
fresh stock, and the other of a cross between plants of the same old
stock.
This species offers another interesting case. In the five first
generations in which intercrossed and self-fertilised plants were put
into competition with one another, every single intercrossed plant beat
its self-fertilised antagonist, except in one instance, in which they
were equal in height. But in the sixth generation a plant appeared,
named by me the Hero, remarkable for its tallness and increased
self-fertility, and which transmitted its characters to the next three
generations. The children of Hero were again self-fertilised, forming
the eighth self-fertilised generation, and were likewise intercrossed
one with another; but this cross between plants which had been subjected
to the same conditions and had been self-fertilised during the seven
previous generations, did not effect the least good; for the
intercrossed grandchildren were actually shorter than the
self-fertilised grandchildren, in the ratio of 100 to 107.
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