For this reason, we will furthermore designate all variations under the
influence of neighbors with the new and special term "vicinism." It
always indicates the result of crossing.
Leaving this somewhat lengthy terminological discussion, we now come to
the description of the phenomenon itself. In visiting the plantations of
the seedsmen in summer and examining the large fields of garden-flowers
from which seed is to be gathered, it is very rare to find a plot quite
pure. On the contrary, occasional impurities are the rule. Every plot
shows anomalous individuals, red or white flowers among a field of blue,
normal among laciniated, single among double and so on. The most curious
instance is afforded by dwarf varieties, where in the midst of hundreds
and thousands of small individuals of the same height, some specimens
show twice their size. So for instance, among the dwarfs of the
larkspur, _Delphinium Ajacis_.
Everywhere gardeners are occupied in destroying these "atavists," as
they call them. When in full bloom the plants are pulled up and thrown
aside. Sometimes the degree of impurity is so high, that great piles of
discarded plants of the same species lie about the [193] paths, as I
have seen at Erfurt in the ease of numerous varieties of the Indian
cress or _Tropaeolum_.
Each variety is purified at the time when it shows its characters most
clearly. With vegetables, this is done long before flowering, but with
flowers only when in full bloom, and with fruits, usually after
fertilization has been accomplished. It needs no demonstration to show
that this difference in method must result in very diverging degrees of
purity.
We will confine ourselves to a consideration of the flowers, and ask
what degree of purity may be expected as the result of the elimination
of the anomalous plants during the period of blooming.
Now it is evident that the colors and forms of the flowers can only be
clearly distinguished, when they are fully displayed. Furthermore it is
impossible to destroy every single aberrant specimen as soon as it is
seen. On the contrary, the gardener must wait until all or nearly all
the individuals of the same variety have displayed their characters, as
only in this way can all diverging specimens be eliminated by a single
inspection. Unfortunately the insects do not wait for this selection.
They fertilize the flowers from the beginning, and the damage will have
been done [194] long before the day of inspection comes around. Crosses
are unavoidable and hybrid seeds will unavoidably come into the harvest.
Their number may be limited by an early eradication of the vicinists, or
by the elimination of the first ripe seeds before the beginning of the
regular harvest, or by other devices. But some degree of impurity will
remain under ordinary circumstances.
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