Lyell, Mr. Logan, Captain Bayfield,
and others, and that the botanical (and zoological as well) region,
essentially northern and Alpine, designated by Professor Schouw that 'of
saxifrages and mosses,' and first in his classification, exists now only on
the flanks of the great area which suffered such conditions; and that,
though similar conditions reappear, the relationship of Alpine and Arctic
vegetation in the southern hemisphere, with that in the northern, is
entirely maintained by 'representative', and not by identical species (the
general truth of my explanation of Alpine floras, including identical
species, becomes so strong, that the view proposed acquires fair claims to
be ranked as a theory, and not considered merely a convenient or bold
hypothesis."] -- Tr.
The
p 349
elk, for instance, lives in the Scandinavian peninsula, almost ten degrees
further north than in the interior of Siberia, where the line of equal
winter temperature is so remarkably concave. Plants migrate in the germ;
and, in the case of many species, the seeds are furnished with organs
adapting them to be conveyed to a distace through the air. When once they
have taken root, they become dependent on the soil and on the strata of air
surrounding them.
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