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Darwin, Charles, 1809-1882

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


Pot 1 : 22 4/8 : 17 4/8.
Pot 2 : 27 4/8 : 24.
Pot 3 : 16 4/8 : 15.
Pot 4 : 22 4/8 : 17.
Total : 89.0 : 73.5.
The four tallest crossed plants averaged 22.25, and the four tallest
self-fertilised 18.37 inches in height; or as 100 to 82. I was surprised
to find that the anthers of a good many of these self-fertilised plants
did not cohere and did not contain any pollen; and the anthers even of a
very few of the crossed plants were in the same condition. Some flowers
on the crossed plants were again crossed, four capsules being thus
obtained; and some flowers on the self-fertilised plants were again
self-fertilised, seven capsules being thus obtained. The seeds from both
lots were weighed, and it was calculated that an equal number of
capsules would have yielded seed in the proportion by weight of 100 for
the crossed to 60 for the self-fertilised capsules. So that the flowers
on the crossed plants again crossed were much more fertile than those on
the self-fertilised plants again self-fertilised.
PLANTS OF THE SECOND GENERATION.
The above two lots of seeds were placed on damp sand, and many of the
crossed seeds germinated, as on the last occasion, before the
self-fertilised, and were rejected. Three or four pairs in the same
state of germination were planted on the opposite sides of two pots; a
single pair in a third pot; and all the remaining seeds were sown
crowded in a fourth pot.


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