How far
these experiments may be trusted, I know not; but the forms experimented on
are ranked by Sagaret, who mainly founds his classification by the test of
infertility, as varieties, and Naudin has come to the same conclusion.
The following case is far more remarkable, and seems at first incredible;
but it is the result of an astonishing number of experiments made during
many years on nine species of Verbascum, by so good an observer and so
hostile a witness as Gartner: namely, that the yellow and white varieties
when crossed produce less seed than the similarly coloured varieties of the
same species. Moreover, he asserts that, when yellow and white varieties
of one species are crossed with yellow and white varieties of a DISTINCT
species, more seed is produced by the crosses between the similarly
coloured flowers, than between those which are differently coloured. Mr.
Scott also has experimented on the species and varieties of Verbascum; and
although unable to confirm Gartner's results on the crossing of the
distinct species, he finds that the dissimilarly coloured varieties of the
same species yield fewer seeds, in the proportion of eighty-six to 100,
than the similarly coloured varieties. Yet these varieties differ in no
respect, except in the colour of their flowers; and one variety can
sometimes be raised from the seed of another.
Kolreuter, whose accuracy has been confirmed by every subsequent observer,
has proved the remarkable fact that one particular variety of the common
tobacco was more fertile than the other varieties, when crossed with a
widely distinct species.
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