The Steppes proper are very fertile elevated plains, slightly undulated, and intersected by numerous ravines which are dry in summer. The undulations are scarcely apparent to the eye as it takes in a wide prospect under a blazing sun and with a deep-blue sky overhead. Not a tree is to be seen, the few woods and thickets being hidden in the depressions and deep valleys of the rivers. On the thick sheet of black earth by which the Steppe is covered a luxuriant vegetation develops in spring; after the old grass has been burned a bright green covers immense stretches, but this rapidly disappears under the burning rays of the sun and the hot easterly winds. The colouring of the Steppe changes as if by magic, and only the silvery plumes of the _kovyl_ (_Stipa pennata_) wave under the wind, giving the Steppe the aspect of a bright, yellow sea. For days together the traveller sees no other vegetation; even this, however, disappears as he nears the regions recently left dry from the Caspian, where salted clays covered with a few _Salsolaceoe_, or mere sands, take the place of the black earth. Here begins the Aral-Caspian desert. The Steppe, however, is not so devoid of trees as at first sight appears. Innumerable clusters of wild cherries, wild apricots, and other deep-rooted shrubs grow in the depressions of the surface, and on the slopes of the ravines, giving the Steppe that charm which manifests itself in popular poetry. Unfortunately, the spread of cultivation is fatal to these oases (they are often called "islands" by the inhabitants); the axe and the plough ruthlessly destroy them. The vegetation of the _poimy_ and _zaimischas_ in the marshy bottoms of the ravines, and in the valleys of streams and rivers, is totally different. The moist soil gives free development to thickets of various willows, bordered with dense walls of worm-wood and needle-bearing _Composita_, and interspersed with rich but not extensive prairies harbouring a great variety of herbaceous plants; while in the deltas of the Black Sea rivers impenetrable masses of rush shelter a forest fauna. But cultivation rapidly changes the physiognomy of the Steppe. The prairies are superseded by wheat-fields, and flocks of sheep destroy the true steppe-grass (_Stipa-pennata_), which retires farther east. The _Circum-Mediterranean Region_ is represented by a narrow strip of land on the south coast of the Crimea, where a climate similar to that of the Mediterranean coast has permitted the development of a flora closely resembling that of the valley of the Arno. [Illustration: REVEL]