The last point which need here be noticed is that, as far as the means of
comparison serve, some degree of relationship generally exists between the
infertility of the illegitimate union of the several parent-forms and that of
their illegitimate offspring. Thus the two illegitimate unions, from which the
plants in Classes 6 and 7 were derived, yielded a fair amount of seed, and only
a few of these plants are in any degree sterile. On the other hand, the
illegitimate unions between plants of the same form always yield very few seeds,
and their seedlings are very sterile. Long-styled parent-plants when fertilised
with pollen from their own-form shortest stamens, appear to be rather more
sterile than when fertilised with their own-form mid-length stamens; and the
seedlings from the former union were much more sterile than those from the
latter union. In opposition to this relationship, short-styled plants
illegitimately fertilised with pollen from the mid-length stamens of the long-
styled form (Class 5) are very sterile; whereas some of the offspring raised
from this union were far from being highly sterile. It may be added that there
is a tolerably close parallelism in all the classes between the degree of
sterility of the plants and their dwarfed stature. As previously stated, an
illegitimate plant fertilised with pollen from a legitimate plant has its
fertility slightly increased.
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