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Vries, Hugo de, 1848-1935

"Species and Varieties, Their Origin by Mutation"


Hence we see that this test would not enable us to judge of the doubtful
cases, although it is quite sufficient as a proof in cases of wider
differences.
Our second assertion related to the reciprocal crosses. This is the name
given to two sexual combinations between the same parents, but with
interchanged places as to which furnishes the pollen. In unbalanced
crosses of the genus _Oenothera_ the hybrids of such reciprocal unions
are often different, as we have previously shown. Sometimes both
resemble the pollen parent more, in other instances the pistil-parent.
In varietal crosses no such divergence is as yet known. It would be
quite superfluous to adduce single cases as proofs for this rule, which
was formerly conceived to hold good for hybrids in general. The work of
the older hybridists, such as Koelreuter and Gaertner affords numerous
instances.
Our third rule is of a wholly different nature. Formerly the distinction
between elementary species and varieties was not insisted upon, and the
principle which stamps retrograde changes [280] as the true character of
varieties is a new one. 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.


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