On the other hand,
the crossed and self-fertilised plants of Mimulus and Primula differed
to an extreme degree in innate fertility, but by no means to a
corresponding degree in height or vigour.
In all the cases of self-fertilised flowers included in Tables 9/E, 9/F,
and 9/G, these were fertilised with their own pollen; but there is
another form of self-fertilisation, namely, by pollen from other flowers
on the same plant; but this latter method made no difference in
comparison with the former in the number of seeds produced, or only a
slight difference. Neither with Digitalis nor Dianthus were more seeds
produced by the one method than by the other, to any trustworthy degree.
With Ipomoea rather more seeds, in the proportion of 100 to 91, were
produced from a crossed between flowers on the same plant than from
strictly self-fertilised flowers; but I have reason to suspect that the
result was accidental. With Origanum vulgare, however, a cross between
flowers on plants propagated by stolons from the same stock certainly
increased slightly their fertility. This likewise occurred, as we shall
see in the next section, with Eschscholtzia, perhaps with Corydalis cava
and Oncidium; but not so with Bignonia, Abutilon, Tabernaemontana,
Senecio, and apparently Reseda odorata.
SELF-STERILE PLANTS.
The cases here to be described might have been introduced in Table 9/F,
which gives the relative fertility of flowers fertilised with their own
pollen, and with that from a distinct plant, but it has been found more
convenient to keep them for separate discussion.
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