| ↑ 1 blocks not present in 1859 1860 1861; present in 1866 1869 1872 |
| Moreover, Gärtner expressly states that hybrids from long-cultivated
plants are more subject to reversion than hybrids from species in their natural state; and this probably explains the singular difference in the results arrived at by different observers: thus, Max Wichura doubts whether hybrids ever revert to their parent- forms,
and he experimented on uncultivated species of willows; whilst Naudin, on the other hand, insists in the strongest terms on the almost universal tendency to reversion in hybrids, and he experimented chiefly on cultivated plants.
|
|
| → resemblance 1859 1860 1861 |
| degrees and kinds of resemblance 1866 1869 1872 |
|
| → With 1859 1860 1861 1866 1869 |
| So I believe it to be with varieties of plants; and with 1872 |
|
| → parent-form, 1859 1860 1866 1869 1872 |
| parent form, by 1861 |
|
|
hybrids: Gärtner states that mongrels are more liable than hybrids to revert to either parent-form; but this, if it be true, is certainly only a difference in degree. ↑
Gärtner further
that when any two species, although most closely allied to each other, are crossed with a third species, the hybrids are widely different from each other;
if two very distinct varieties of one species are crossed with another species, the hybrids do not differ much. But this conclusion, as far as I can make out, is founded on a single experiment; and seems directly opposed to the results of several experiments made by Kölreuter. |
|
|
alone are the unimportant
which Gärtner is able to point
between hybrid and mongrel plants. On the other hand, the
→resemblance
in mongrels and in hybrids to their respective parents, more especially in hybrids produced from nearly related species,
according to Gärtner the same laws. When two species are crossed, one has sometimes a prepotent power of impressing its likeness on the
→With
animals one variety certainly often has this prepotent power over another variety. Hybrid plants produced from a reciprocal cross, generally resemble each other closely; and so it is with
a reciprocal cross. Both hybrids and mongrels can be reduced to either pure
→parent-form,
repeated crosses in successive generations with either parent. |
|
| These several remarks are apparently applicable to animals; but the subject is here
complicated, partly owing to the existence of secondary sexual characters; but more especially owing to prepotency in transmitting likeness running more strongly in one sex than in the other, both when one species is crossed with another, and when one variety is crossed with
|
