Comparison with 1859 |
|
be
no special mechanical contrivance to prevent the stigma of a flower receiving its own pollen,
yet, as C. C. Sprengel has
shown, and as I can confirm, either the anthers burst before the stigma is ready for fertilisation, or the stigma is ready before the pollen of that flower is ready, so that these plants
have in fact separated sexes, and must habitually be crossed. ↑1 blocks not present in 1859 1860 1861; present in 1866 1869 1872 | So it is with the reciprocally dimorphic and trimorphic plants previously alluded to.
|
How strange are these facts! How strange that the pollen and stigmatic surface of the same flower, though placed so close together, as if for the very purpose of self-fertilisation, should in so many cases be
mutually useless to each other! How simply are these facts explained on the view of an occasional cross with a distinct individual being advantageous or indispensable! |
|
If several varieties of the cabbage, radish, onion, and of some other plants, be allowed to seed near each other, a large majority,
as I have found,
of the seedlings thus raised will
turn out
mongrels:
for instance, I raised 233 seedling cabbages from some plants of different varieties growing near each other, and of these only 78 were true to their kind, and some even of these were not perfectly true. Yet the pistil of each cabbage-flower is surrounded not only by its own six stamens, but by those of the many other flowers on the same plant.
↑1 blocks not present in 1859 1860; present in 1861 1866 1869 1872 | and the pollen of each flower readily gets on its own stigma without insect agency;
for I have found that plants
carefully protected from insects
produce
the full number of pods.
|
How, then, comes it that such a vast number of the seedlings are mongrelized? I suspect that it
must arise from the pollen of a distinct
variety
having a prepotent effect over a
flower's
own pollen; and that this is part of the general law of good being derived from the intercrossing of distinct individuals of the same species. When distinct
species
are crossed the case is directly the
reverse,
for a plant's
own pollen is always
prepotent over foreign pollen; but to this subject we shall return in a future chapter. |
|
In the case of a gigantic
tree covered with
innumerable innumerable 1859 1861 1866 1869 1872 | innume- rable 1860 |
|
be be 1859 1860 1861 1866 1869 | is 1872 |
no special mechanical contrivance to prevent the stigma
of a flower receiving its own pollen, of a flower receiving its own pollen, 1859 1860 1861 1866 1869 |
receiving pollen from the same flower, 1872 |
yet, as
C. C. Sprengel has C. C. Sprengel has 1859 1860 1861 1866 1869 |
Sprengel, and more recently Hildebrand, and others, have 1872 |
shown, and as I can confirm, either the anthers burst before the stigma is ready for fertilisation, or the stigma is ready before the pollen of that flower is ready, so that these
plants plants 1859 1860 1861 1866 1869 |
so-named dichogamous plants 1872 |
have in fact separated sexes, and must habitually be crossed. ↑1 blocks not present in 1859 1860 1861; present in 1866 1869 1872 | So it is with the reciprocally dimorphic and trimorphic plants previously alluded to.
|
How strange are these facts! How strange that the pollen and stigmatic surface of the same flower, though placed so close together, as if for the very purpose of self-fertilisation, should
in so many cases be in so many cases be 1859 1860 1861 1866 1869 |
be in so many cases 1872 |
mutually useless to each
other! other! 1859 1860 1861 1866 1869 | other? 1872 |
How simply are these facts explained on the view of an occasional cross with a distinct individual being advantageous or indispensable! |
|
If several varieties of the cabbage, radish, onion, and of some other plants, be allowed to seed near each other, a large
majority, majority, 1859 1860 1861 1866 1869 | majority 1872 |
as I have found, as I have found, 1859 1860 1861 1866 1869 |
OMIT 1872 |
of the seedlings thus raised
will will 1859 1860 1861 1866 1869 | will 1872 |
turn
out out 1859 1860 1861 1866 1869 | out, 1872 |
mongrels: mongrels: 1859 1860 1861 1866 1869 |
as I have found, mongrels: 1872 |
for instance, I raised 233 seedling cabbages from some plants of different varieties growing near each other, and of these only 78 were true to their kind, and some even of these were not perfectly true. Yet the pistil of each cabbage-flower is surrounded not only by its own six stamens, but by those of the many other flowers on the same
plant. plant. 1859 1860 | plant; 1861 1866 1869 1872 |
How, then, comes it that such a vast number of the seedlings are mongrelized?
I suspect that it I suspect that it 1859 1860 1861 1866 1869 |
It 1872 |
must arise from the pollen of a distinct
variety
having a prepotent effect over
a a 1859 1860 1861 1866 1869 | the 1872 |
flower's flower's 1859 1860 1861 1866 1872 | flowers 1869 |
own pollen; and that this is part of the general law of good being derived from the intercrossing of distinct individuals of the same species. When distinct
species
are crossed the case is
directly the directly the 1859 1860 1866 1869 | directly the 1872 |
reverse, reverse, 1859 1860 1866 1869 | reversed, 1872 |
for a
plant's plant's 1859 1860 1866 1872 | plants 1869 |
own pollen is
always always 1859 1860 | almost always 1866 1869 1872 |
prepotent over foreign pollen; but to this subject we shall return in a future chapter. |
|
In the case of a
gigantic gigantic 1859 1860 1861 1866 | large 1869 1872 |
tree covered with
innume- rable innume- rable 1860 | innumerable 1859 1861 1866 1869 1872 |
|