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Darwin, Charles, 1809-1882

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


Several single-flowered carnations were planted in good soil, and were
all covered with a net. Eight flowers were crossed with pollen from a
distinct plant and yielded six capsules, containing on an average 88.6
seeds, with a maximum in one of 112 seeds. Eight other flowers were
self-fertilised in the manner above described, and yielded seven
capsules containing on an average 82 seeds, with a maximum in one of 112
seeds. So that there was very little difference in the number of seeds
produced by cross-fertilisation and self-fertilisation, namely, as 100
to 92. As these plants were covered by a net, they produced
spontaneously only a few capsules containing any seeds, and these few
may perhaps be attributed to the action of Thrips and other minute
insects which haunt the flowers. A large majority of the spontaneously
self-fertilised capsules produced by several plants contained no seeds,
or only a single one. Excluding these latter capsules, I counted the
seeds in eighteen of the finest ones, and these contained on an average
18 seeds. One of the plants was spontaneously self-fertile in a higher
degree than any of the others. On another occasion a single covered-up
plant produced spontaneously eighteen capsules, but only two of these
contained any seed, namely 10 and 15.
CROSSED AND SELF-FERTILISED PLANTS OF THE FIRST GENERATION.
The many seeds obtained from the above crossed and artificially
self-fertilised flowers were sown out of doors, and two large beds of
seedlings, closely adjoining one another, thus raised.


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print 'generali 1171501668' . "\n"; print 'porównanie oc 1171501669' . "\n"; print 'usługi remontowe Chorzów 1171501817' . "\n"; print 'Viagra print 'wykładziny dywanowe 1171501983' . "\n";