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Darwin, Charles, 1809-1882

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

Nemophila insignis.
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Self-fertilised Plants from Crossed Plants.
Column 3: Self-fertilised Plants from Self-fertilised Plants.
Pot 1 : 27 : 27 4/8.
Pot 1 : 14 : 34 2/8.
Pot 2 : 17 6/8 : 23.
Pot 2 : 24 4/8 : 32.
Pot 3 : 16 : 7.
Pot 4 : 5 3/8 : 7 2/8.
Pot 4 : 5 4/8 : 16.
Total : 110.13 : 147.00.
23. BORAGINACEAE.--Borago officinalis.
This plant is frequented by a greater number of bees than any other one
which I have observed. It is strongly proterandrous (H. Muller
'Befruchtung' etc. page 267), and the flowers can hardly fail to be
cross-fertilised; but should this not occur, they are capable of
self-fertilisation to a limited extent, as some pollen long remains
within the anthers, and is apt to fall on the mature stigma. In the year
1863 I covered up a plant, and examined thirty-five flowers, of which
only twelve yielded any seeds; whereas of thirty-five flowers on an
exposed plant growing close by, all with the exception of two yielded
seeds. The covered-up plant, however, produced altogether twenty-five
spontaneously self-fertilised seeds; the exposed plant producing
fifty-five seeds, the product, no doubt, of cross-fertilisation.
In the year 1868 eighteen flowers on a protected plant were crossed with
pollen from a distinct plant, but only seven of these produced fruit;
and I suspect that I applied pollen to many of the stigmas before they
were mature.


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