on the Urals, 71 deg. on West Siberia). The shortness of summer,
the deficiency of drainage and the thickness of the layer of soil
which is frozen through in winter are the elements which go to
the making of the characteristic features of the _tundras_. Their
flora is far nearer those of northern Siberia and North America
than that of central Europe. Mosses and lichens cover them, as
also the birch, the dwarf willow, and a variety of shrubs; but
where the soil is drier, and humus has been able to accumulate, a
variety of herbaceous flowering plants, some of which are familiar
also in western Europe, make their appearance.
The _Forest Region_ of the Russian botanists occupies the greater
part of the country, from the Arctic _tundras_ to the Steppes, and
it maintains over this immense surface a remarkable uniformity
of character. Viewed as a whole, the flora of the forest region
must be regarded as European-Siberian; and though certain species
disappear towards the east, while new ones make their appearance,
it maintains, on the whole, the same characters throughout from
Poland to Kamchatka.
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