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324 of dwarf trees and scrub, chiefly birch, willow, juniper, and conifers, not infrequently appear along the southern margin of the tundras.

3. The most characteristic animal forms are lemmings, arctic fox, arctic hare, musk ox, and reindeer. Of common occurrence also are various voles, ermine, and weasel. Their range, however, is hardly so far north, and they go much farther south. So again the wolf, the ubiquitous common fox, and the brown bear, are frequent visitants rather than common denizens of the tundras.

4. In summer many of the animals just named push farther north, while swarms of birds (especially water birds) visit every part of the treeless zone.

5. Lastly, in winter, storms of snow and dust are common.

We may now take a similar brief glance at the steppe lands of Europe and Asia. The regions included under this head show considerable variety. Some steppes are mere desert wastes while others are fertile tracts capable of high cultivation. Many are low plains, others are elevated plateaus, the former having a subarctic, the latter a subtropical climate; and between low and high steppes many gradations are met with. All are more or less characterized by an extreme range of temperature. The steppes with which we are at present concerned, however, are the generally low grassy plains which Professor Nehring designates the subarctic steppes. These occupy wide areas in south- east Russia and southwest Siberia, extending between the middle course of the Volga and that of the Irtysch. It is quite a mistake to suppose that these steppes are throughout all their extent treeless plains. In many places chains and irregular groups of hills diversify the surface, while here and there trees of various kinds, such as pines, larches, birches, oaks, limes, alders, willows, wild apples, and others, are more or less plentiful. Many of the woods are mere oases, extending along the banks of rivers and streams, or clustering around the margins of fresh-water lakes. In southeast Russia the boundary between the steppes and the forest lands is very irregular—the two regions constantly interosculate.

The climate of these subarctic steppes is quite continental, the summer being relatively warm and the winter relatively cold. The average temperature in January hardly exceeds 3° F. while that of July is at least 70°. Again, the rainfall is very uncertain. In some years it is excessive, in others meager, while occasionally it altogether fails. With the approach of spring vegetation rapidly develops, becoming rank and luxuriant, but with the heat of summer it quickly fades and withers away. Severe frost, and frequently heavy snowstorms, characterize the winter. In such areas as are more or less wooded the climate is somewhat less continental, the summers being relatively less dry and the winters not so cold. But even in those wooded regions the seasons are strongly contrasted. In general, we may say the steppe lands in summer are practically rainless. The ground is thus parched and burnt