I have also
elsewhere shown that with Primula veris and sinensis, equal-styled
varieties occasionally appear which possess the sexual organs of the two
forms combined in the same flower. (9/16. 'Journal of the Linnean
Society Botany' volume 10 1867 pages 417, 419.) Consequently they
fertilise themselves in a legitimate manner and are highly self-fertile;
but the remarkable fact is that they are rather more fertile than
ordinary plants of the same species legitimately fertilised by pollen
from a distinct individual. Formerly it appeared to me probable, that
the increased fertility of these dimorphic plants might be accounted for
by the stigma lying so close to the anthers that it was impregnated at
the most favourable age and time of the day; but this explanation is not
applicable to the above given cases, in which the flowers were
artificially fertilised with their own pollen.
Considering the facts now adduced, including the appearance of those
varieties which are more fertile and taller than their parents and than
the intercrossed plants of the corresponding generation, it is difficult
to avoid the suspicion that self-fertilisation is in some respects
advantageous; though if this be really the case, any such advantage is
as a rule quite insignificant compared with that from a cross with a
distinct plant, and especially with one of a fresh stock. Should this
suspicion be hereafter verified, it would throw light, as we shall see
in the next chapter, on the existence of plants bearing small and
inconspicuous flowers which are rarely visited by insects, and therefore
are rarely intercrossed.
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