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Darwin, Charles, 1809-1882

"Effects of Cross and Self Fertilisation in the Vegetable Kingdom"

On this view, also, the large size
of the stigmatic surface is an unintelligible feature in the structure
of the flower, as well as the relative position of all the parts, which
is such that when insects visit the flowers to suck the copious nectar,
they cannot fail to carry pollen from one flower to another. (6/7.
Delpino has described 'Bot. Zeitung' 1867 page 277 and 'Scientific
Opinion' 1870 page 135, the structure of the flowers in this genus, but
he was mistaken in thinking that self-fertilisation is impossible, at
least in the case of the present species. Dr. Dickie and Professor
Faivre state that the flowers are fertilised in the bud, and that
self-fertilisation is inevitable. I presume that they were misled by the
pollen being deposited at a very early period on the pistil: see
'Journal of Linnean Society Botany' volume 10 page 55 and 'Variabilit?
des Esp?ces' 1868 page 158.)
According to Delpino, bees eagerly visit the flowers in North Italy, but
I have never seen any insect visiting the flowers of the present species
in my hothouse, although many plants grew there during several years.
Nevertheless these plants produced plenty of seed, as they likewise did
when covered by a net; they are therefore fully capable of
self-fertilisation, and have probably been self-fertilised in this
country for many generations. As they are cultivated in pots, and are
not exposed to competition with surrounding plants, they have also been
subjected for a considerable time to somewhat uniform conditions.


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