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Darwin, Charles, 1809-1882

"The Different Forms of Flowers on Plants of the Same Species"

Eight flowers on these same short-
styled plants, and the one long-styled illegitimate plant were reciprocally and
legitimately crossed; they produced five capsules, which contained an average of
28.6 seeds, with a maximum of 36. A reciprocal cross between legitimate plants
of the two forms would have yielded an average of at least 57 seeds, with a
possible maximum of 74 seeds; so that these illegitimate plants were sterile
when legitimately crossed.
I succeeded in raising from the above seven short-styled illegitimate plants,
fertilised with their own-form pollen, only six plants--grandchildren of the
first union. These, like their parents, were of low stature, and had so poor a
constitution that four died before flowering. With ordinary plants it has been a
rare event with me to have more than a single plant die out of a large lot. The
two grandchildren which lived and flowered were short-styled; and twelve of
their flowers were fertilised with their own-form pollen and produced twelve
capsules containing an average of 28.2 seeds; so that these two plants, though
belonging to so weakly a set, were rather more fertile than their parents, and
perhaps not in any degree sterile. Four flowers on the same two grandchildren
were legitimately fertilised by a long-styled illegitimate plant, and produced
four capsules, containing only 32.


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