In only one out of the eleven
cases in Table 7/B, that of Eschscholtzia, do the self-fertilised plants
exceed the crossed in weight; and we have already seen they are likewise
superior to them in height, though inferior in fertility, the whole
advantage of a cross being here confined to the reproductive system.
With Vandellia the crossed plants were a little heavier, as they were
also a little taller than the self-fertilised; but as a greater number
of more productive capsules were produced by the cleistogene flowers on
the self-fertilised plants than by those on the crossed plants, the case
must be left, as remarked under Table 7/A, altogether doubtful. The
crossed and self-fertilised offspring from a partially self-sterile
plant of Reseda odorata were almost equal in weight, though not in
height. In the remaining eight cases, the crossed plants show a
wonderful superiority over the self-fertilised, being more than double
their weight, except in one case, and here the ratio is as high as 100
to 67. The results thus deduced from the weights of the plants confirm
in a striking manner the former evidence of the beneficial effects of a
cross between two plants of the same stock; and in the few cases in
which plants derived from a cross with a fresh stock were weighed, the
results are similar or even more striking.
CHAPTER VIII.
DIFFERENCE BETWEEN CROSSED AND SELF-FERTILISED PLANTS IN CONSTITUTIONAL
VIGOUR AND IN OTHER RESPECTS.
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