| → receiving pollen from the same flower, 1872 |
| of a flower receiving its own pollen, 1859 1860 1861 1866 1869 |
|
| → Sprengel, and more recently Hildebrand, and others, have 1872 |
| C. C. Sprengel has 1859 1860 1861 1866 1869 |
|
| → so-named dichogamous plants 1872 |
| plants 1859 1860 1861 1866 1869 |
|
| → be in so many cases 1872 |
| in so many cases be 1859 1860 1861 1866 1869 |
|
| → OMIT 1872 |
| as I have found, 1859 1860 1861 1866 1869 |
|
| → as I have found, mongrels: 1872 |
| mongrels: 1859 1860 1861 1866 1869 |
|
| → It 1872 |
| I suspect that it 1859 1860 1861 1866 1869 |
|
| → OMIT 1872 |
| we can see that 1859 1860 1861 1866 1869 |
|
|
freely in my garden. In very many other cases, though there
no special mechanical contrivance to prevent the stigma
→receiving pollen from the same flower,
yet, as
→Sprengel, and more recently Hildebrand, and others, have
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
→so-named dichogamous plants
have in fact separated sexes, and must habitually be crossed. 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
→be in so many cases
mutually useless to each
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
→OMIT
of the seedlings thus raised
turn
→as I have found, 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
and the pollen of each flower readily gets on its own stigma without
for I have found that
carefully protected
the full number of pods. How, then, comes it that such a vast number of the seedlings are mongrelized?
→It
must arise from the pollen of a distinct
variety
having a prepotent effect over
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
for a
own pollen is
prepotent over foreign pollen; but to this subject we shall return in a future chapter. |
|
| In the case of a
tree covered with
flowers, it may be objected that pollen could seldom be carried from tree to tree, and at most only from flower to flower on the same
and
flowers on the same tree can be considered as distinct individuals only in a limited sense. I believe this objection to be valid, but that nature has largely provided against it by giving to trees a strong tendency to bear flowers with separated sexes. When the sexes are separated, although the male and female flowers may be produced on the same tree,
→OMIT
pollen must
|
