626 ZONES AND REGIONS [Pt. Ill, Sect. II 



The most characteristic plant of the desert of Central Asia is Haloxylon 

 Ammodendron, a small chenopodiaceous tree, attaining six meters in height, 

 with leafless branches and a relatively thick trunk (Fig. 358). It has a very 

 hard, heavy wood, and an extremely juicy bark, apparently serving as a water- 

 reservoir ; in May it bears small yellow flowers, and in September top-shaped, 

 somewhat fleshy fruits. It frequently forms small woods. 



Among the striking and very widely spread plants may also be placed 

 Lasiagrostis splendens, a grass attaining over two and a half meters in height, 

 which grows chiefly on saline clay soil and forms extensive thickets in favour- 

 able spots. 



Quite common but less characteristic is a zygophyllaceous plant, Nitraria 

 Schoberi, which extends to South Russia and also into Australia. It is 

 a small-leaved, somewhat succulent and thorny shrub, thriving best on saline 

 clay soil and attaining a height of thirty centimeters. Its berries are greedily 

 eaten by all desert animals. 



Among the larger plants are also species of Tamarix, for instance, T. Pal- 

 lasii, attaining a height of three meters. 



Descriptions of the plant-formations in the Western and Central Asiatic 

 deserts are not available, at any rate in the languages of Western Europe, 

 with the exception of the following sketch, written by von Herder from an 

 account by Krasnov 1 , of the extreme western border of the desert on the 

 lower Volga : — 



'The chief characteristics of this wormwood-steppe formation 2 consist in the low 

 growth of the plants belonging to it, in these being separated from one another 

 by wide stretches of bare soil, and above all in the predominance of greyish- 

 green herbs which are provided with hairs that shoot out vigorously under the sun's 

 rays and are rich in aromatic ethereal oils. Different species follow one another in 

 time in this steppe in unusually rapid and frequent succession, for, after the appear- 

 ance of new forms, often not a trace remains of the old ones that have blossomed. 

 The steppe is really never completely dried up, although for a long period it looks 

 so. The deceptive appearance is due to the fact that usually very few species with 

 bright flower are in blossom, except in early spring, when delicate and juicy herbs 

 belonging to the Ranunculaceae, Cruciferae, Papaveraceae, Liliaceae, and, among 

 grasses, Poa bulbosa, predominate. Later on, they are replaced by Achillea Gerberi 

 and by the general mass of the grasses with rolled and stiff leaves. Then follow, 

 pari passu with increasing dryness and heat, Alhagi camelorum, Xanthium spino- 

 sum, Ceratocarpus arenarius, and Eryngium campestre, all of them abnormally 

 thorny plants whose spring covering of delicate leaves gives place in dry weather to 

 projecting thorns. Finally, at the end of summer, there is a complete predominance 

 of species of wormwood (Artemisia frigida and A. maritima) and of halophytic 

 herbs, whose roots, descending to a depth of fourteen feet, thus obtain sufficient 

 moisture for these plants when all their neighbours are dying from drought.' 



1 Krasnov, op. cit. 



2 According to our terminology this is to be reckoned among desert formations. 



