The plants in the three rows were
exactly of the same age and had been subjected to closely similar
conditions, so that any difference in their fertility must be attributed
to their different origin; namely, to the one lot being derived from
plants self-fertilised for four generations and then crossed with a
fresh stock; to the second lot being derived from plants of the same old
stock intercrossed for five generations; and to the third lot being
derived from plants self-fertilised for five generations. All the
capsules, some nearly mature and some only half-grown, were gathered,
counted, and weighed from the ten finest plants in each of the three
rows, of which the measurements and weights have already been given. The
intercrossed plants, as we have seen, were taller and considerably
heavier than the plants of the other two lots, and they produced a
greater number of capsules than did even the Westerham-crossed plants;
and this may be attributed to the latter having grown more crowded and
being in consequence less branched. Therefore the average weight of an
equal number of capsules from each lot of plants seems to be the fairest
standard of comparison, as their weights will have been determined
chiefly by the number of the included seeds. As the intercrossed plants
were taller and heavier than the plants of the other two lots, it might
have been expected that they would have produced the finest or heaviest
capsules; but this was very far from being the case.
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