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Darwin, Charles, 1809-1882

"The Origin of Species by means of Natural Selection, 6th Edition"

He experimented on
some of the very same species as did Gartner. The difference in their
results may, I think, be in part accounted for by Herbert's great
horticultural skill, and by his having hot-houses at his command. Of his
many important statements I will here give only a single one as an example,
namely, that "every ovule in a pod of Crinum capense fertilised by C.
revolutum produced a plant, which I never saw to occur in a case of its
natural fecundation." So that here we have perfect, or even more than
commonly perfect fertility, in a first cross between two distinct species.
This case of the Crinum leads me to refer to a singular fact, namely, that
individual plants of certain species of Lobelia, Verbascum and Passiflora,
can easily be fertilised by the pollen from a distinct species, but not by
pollen from the same plant, though this pollen can be proved to be
perfectly sound by fertilising other plants or species. In the genus
Hippeastrum, in Corydalis as shown by Professor Hildebrand, in various
orchids as shown by Mr. Scott and Fritz Muller, all the individuals are in
this peculiar condition. So that with some species, certain abnormal
individuals, and in other species all the individuals, can actually be
hybridised much more readily than they can be fertilised by pollen from the
same individual plant! To give one instance, a bulb of Hippeastrum aulicum
produced four flowers; three were fertilised by Herbert with their own
pollen, and the fourth was subsequently fertilised by the pollen of a
compound hybrid descended from three distinct species: the result was that
"the ovaries of the three first flowers soon ceased to grow, and after a
few days perished entirely, whereas the pod impregnated by the pollen of
the hybrid made vigorous growth and rapid progress to maturity, and bore
good seed, which vegetated freely.


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