On the other hand, the present
species of Specularia appears to set almost as many capsules when
covered up, as when left to the visits of the Diptera, which, as far as
I have seen, are the only insects that frequent the flowers. (5/20. It
has long been known that another species of the genus, Specularia
perfoliata, produces cleistogene as well as perfect flowers, and the
former are of course self-fertile.) I did not ascertain whether the
naturally crossed and spontaneously self-fertilised capsules contained
an equal number of seeds, but a comparison of artificially crossed and
self-fertilised flowers, showed that the former were probably the most
productive. It appears that this plant is capable of producing a large
number of self-fertilised capsules owing to the petals closing at night,
as well as during cold weather. In the act of closing, the margins of
the petals become reflexed, and their inwardly projecting midribs then
pass between the clefts of the stigma, and in doing so push the pollen
from the outside of the pistil on to the stigmatic surfaces. (5/21. Mr.
Meehan has lately shown 'Proceedings of the Academy of Natural Science
Philadelphia' May 16, 1876 page 84, that the closing of the flowers of
Claytonia virginica and Ranunculus bulbosus during the night causes
their self-fertilisation.)
Twenty flowers were fertilised by me with their own pollen, but owing to
the bad season, only six capsules were produced; they contained on an
average 21.
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