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Updated: September 12, 2025
Therefore it is necessary to cite a considerable amount of evidence in order to prove the assertion that a hybrid bears the active character of its parent-species and not the inactive character of the variety chosen for the cross. We may put this assertion in a briefer form, stating that the active character prevails in the hybrid over its dormant antagonist.
So that we might obtain the parent-species and its several modified descendants from the lower and upper beds of a formation, and unless we obtained numerous transitional gradations, we should not recognise their relationship, and should consequently be compelled to rank them all as distinct species.
He is as emphatic in his conclusion that some hybrids are perfectly fertile as fertile as the pure parent-species as are Kölreuter and Gärtner that some degree of sterility between distinct species is a universal law of nature. He experimentised on some of the very same species as did Gärtner.
By the theory of natural selection all living species have been connected with the parent-species of each genus, by differences not greater than we see between the varieties of the same species at the present day; and these parent-species, now generally extinct, have in their turn been similarly connected with more ancient species; and so on backwards, always converging to the common ancestor of each great class.
In India, however, these cross-bred geese must be far more fertile; for I am assured by two eminently capable judges, namely Mr. Blyth and Capt. Hutton, that whole flocks of these crossed geese are kept in various parts of the country; and as they are kept for profit, where neither pure parent-species exists, they must certainly be highly fertile.
Varieties generally have much restricted ranges: this statement is indeed scarcely more than a truism, for if a variety were found to have a wider range than that of its supposed parent-species, their denominations ought to be reversed.
O. cruciata grows in the Adirondack Mountains, in the states of New York and Vermont, and seems to be abundant there. It has been introduced into botanical gardens and yielded a number of hybrids, especially with O. biennis and O. lamarckiana, and the narrow petals of the parent-species may be met with in combination with the stature and vegetative characteristics of these last named species.
But in these and in many other cases, Gärtner is obliged carefully to count the seeds, in order to show that there is any degree of sterility. He always compares the maximum number of seeds produced by two species when crossed and by their hybrid offspring, with the average number produced by both pure parent-species in a state of nature.
Finally, we have seen that natural selection, which results from the struggle for existence, and which almost inevitably induces extinction and divergence of character in the many descendants from one dominant parent-species, explains that great and universal feature in the affinities of all organic beings, namely, their subordination in group under group.
There are certain hybrids which, instead of having, as is usual, an intermediate character between their two parents, always closely resemble one of them; and such hybrids, though externally so like one of their pure parent-species, are with rare exceptions extremely sterile.
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