thin itself, or
rather a satellite attached to America; whence it has derived a few
stray colonists, and has received the general character of its
indigenous productions. One is astonished," he adds, "at the amount of
creative force displayed on so many small, barren, and rocky islands,
and still more so, at its diverse, yet analogous action on points so
near each other. I have said that the Galapagos archipelago might be
called a satellite attached to America, but it should rather be called a
group of satellites physically similar, organically distinct, yet
intimately related to each other, and all related in a marked, though
much lesser degree, to the great American continent."[848]

_Number of botanical provinces._--De Candolle has enumerated twenty
great botanical provinces inhabited by indigenous or aboriginal plants;
and although many of these contain a variety of species which are common
to several others, and sometimes to places very remote, yet the lines of
demarcation are, upon the whole, astonishingly well defined.[849] Nor is
it likely that the bearing of the evidence on which these general views
are founded will ever be materially affected, since they are already
confirmed by the examination of nearly one hundred thousand species of
plants.

The entire change of opinion which the contemplation of those phenomena
has brought about is worthy of remark. The first travellers were
persuaded that they should find, in distant regions, the plants of their
own country, and they took a pleasure in giving them the same names. It
was some time before this illusion was dissipated; but so fully sensible
did botanists at last become of the extreme smallness of the number of
phaenogamous plants common to different continents, that the ancient
Floras fell into disrepute. All grew diffident of the pretended
identifications; and we now find that every naturalist is inclined to
examine each supposed exception with scrupulous severity.[850] If they
admit the fact, they begin to speculate on the mode whereby the seeds
may have been transported from one country into the other, or enquire on
which of two continents the plant was indigenous, assuming that a
species, like an individual, cannot have two birthplaces.

_Marine vegetation._--The marine vegetation is divisible into different
systems, like those prevailing on the land; but they are much fewer, as
we might have expected, the temperature of the ocean being more uniform
t