, 1877-03-17


of other :"ees in common with the whole
northern hemisphere, yet leaving them
out of view, the vegetation OF California
is strikingly unlike that of the Atlantic
States. That almost all the ch hlracteris.
tic forms Of vegetation of the Atlantic
States are wanting in California; while
those of California are wanting in the
Atlantic States. The near relatives of
most of the California vegetation, such
rs they have, are to be found southward,
on the Mexican plateau, or many as far
south as Chill. This may he
said of the plants of the
intervening great Plains, except that
northward in the suhsaline vegetation
there are some close alliances with the
fora Of the steppes Of Siberia, and along
the crestS Of high mountain ranges the
Arctic Alpine flora has sent southward
more or less numerous representatives
through the whole length of the country.
The differences in vegetation between
the two sides OF the continent growing
less and less as we 90 north, in the
latitude of Lake Superior, where
on more rainy line, trees Of the Attain
tic forest and that of Oregon may be
said to intermiX.
The fora OF California is different
from that Of Eastern Asia, as from the
Atlantic States while between Eastern
North America and Eastern Asia there is
an astonishing similarity. There are types
which appear to have reached the Allan
tic States from the South; and there is IL
large infusion Of sub.tropical Asiatic
types into temperate China and Japan :;
among these there is no relationship to
speak OF. Besides these there are spe-
cies common to the whole northern
hemisphere, without special significance
for this article. "The point to be re-
marked is that many or even most of the
genera and species which are peculiar to
North America as compared with Eu-
rope, and largely peculiar to Atlantic
North America as compared with the
California region, are also represented
in Japan and Mantchooria, either by
identical or by closely similar forms.
These repetitions are IN all degrees Of
likeness ; sometimes the one is undistin-
gulshable from the other; sometimes
tFre Is difference Of aspect but hardly
OF tangible character sometimes the
two would be termed marked varieties
if they grew naturally in the same forest
or in the same region sometimes they
are what the botanist calls representa-
tive species, the one answering closely to
the other, but with some differences re
garded as specific sometimes the two
are merely OF the same genus, or not
quite that, but of Il single or very few
species IN each country in which case
the point which interests US is, that this
peculiar limited type should occur in
two antipodal places, and nowhere else.
"These singular relations attracted my
curiosity early in the course OF my bo.
tanical studies, when comparatively few
Of them were known, and my serious at.
tention in later years when | had nu
merous and new japanese plants to
study. This was before Heer
had developed tina rich fossil botany of
the Arctic zone, before the immense an.
tiquity of existing species of plants was
recognized, and before the publication of
Darwin's now famous volume on the
"Origin OF Species had introduced and
familiarized the scientific world with
those now current ideas respecting the
history and vicissitules Of species. y y
Ny speculation was based upon the
former glaciatiOn OF the northcan tenn.
perate zone, and the inference of a
werner period preceding and perhaps
following | consider that our own
present vegetation, or its proXimate an.
ancestry, must have occupied the arctic
and subarctic regions in Pliocehe times,
and that it had been gradually pushed
southwark as the temperature lowered
and the glaciatIon advanced, even be.
yond its present habitation that plant
OF the same stock and kindred, probably
ranging round the Arctic zone as the
present Arctic species do, made their
forced migration southwark upon wide.
ly different longitudes, and reccdcd more
or less as the climate grew warmer; that