Lastly, seedlings raised from a cross between flowers on the same plant
were not superior to those from flowers fertilised with their own
pollen; but this result cannot be absolutely trusted, owing to some
previous observations, which, however, were made under very unfavourable
circumstances.
[Digitalis purpurea.
The flowers of the common Foxglove are proterandrous; that is, the
pollen is mature and mostly shed before the stigma of the same flower is
ready for fertilisation. This is effected by the larger humble-bees,
which, whilst in search of nectar, carry pollen from flower to flower.
The two upper and longer stamens shed their pollen before the two lower
and shorter ones. The meaning of this fact probably is, as Dr. Ogle
remarks, that the anthers of the longer stamens stand near to the
stigma, so that they would be the most likely to fertilise it (3/3.
'Popular Science Review' January 1870 page 50.); and as it is an
advantage to avoid self-fertilisation, they shed their pollen first,
thus lessening the chance. There is, however, but little danger of
self-fertilisation until the bifid stigma opens; for Hildebrand found
that pollen placed on the stigma before it had opened produced no
effect. (3/4. 'Geschlechter-Vertheilung bei den Pflanzen' 1867 page 20.)
The anthers, which are large, stand at first transversely with respect
to the tubular corolla, and if they were to dehisce in this position
they would, as Dr.
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