This
variety seems to have become specially adapted to profit in every way by
self-fertilisation, although this process was so injurious to the
parent-plants during the first four generations. It should however be
remembered that seedlings raised from this variety, when crossed by a
fresh stock, were wonderfully superior in height and fertility to the
self-fertilised plants of the corresponding generation.
Secondly, in the sixth self-fertilised generation of Ipomoea a single
plant named the Hero appeared, which exceeded by a little in height its
intercrossed opponent,--a case which had not occurred in any previous
generation. Hero transmitted the peculiar colour of its flowers, as well
as its increased tallness and a high degree of self-fertility, to its
children, grandchildren, and great-grandchildren. The self-fertilised
children of Hero were in height to other self-fertilised plants of the
same stock as 100 to 85. Ten self-fertilised capsules produced by the
grandchildren contained on an average 5.2 seeds; and this is a higher
average than was yielded in any other generation by the capsules of
self-fertilised flowers. The great-grandchildren of Hero derived from a
cross with a fresh stock were so unhealthy, from having been grown at an
unfavourable season, that their average height in comparison with that
of the self-fertilised plants cannot be judged of with any safety; but
it did not appear that they had profited even by a cross of this kind.
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