For the
surrounding plants absorb different amounts of various substances from
the soil, and thus greatly affect the nourishment and even the life of
the individuals of any particular species. These will also be shaded and
otherwise affected by the nature of the surrounding plants. Moreover,
seeds often lie dormant in the ground, and those which germinate during
any one year will often have been matured during very different seasons.
Seeds are widely dispersed by various means, and some will occasionally
be brought from distant stations, where their parents have grown under
somewhat different conditions, and the plants produced from such seeds
will intercross with the old residents, thus mingling their
constitutional peculiarities in all sorts of proportions.
Plants when first subjected to culture, even in their native country,
cannot fail to be exposed to greatly changed conditions of life, more
especially from growing in cleared ground, and from not having to
compete with many or any surrounding plants. They are thus enabled to
absorb whatever they require which the soil may contain. Fresh seeds are
often brought from distant gardens, where the parent-plants have been
subjected to different conditions. Cultivated plants like those in a
state of nature frequently intercross, and will thus mingle their
constitutional peculiarities. On the other hand, as long as the
individuals of any species are cultivated in the same garden, they will
apparently be subjected to more uniform conditions than plants in a
state of nature, as the individuals have not to compete with various
surrounding species.
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