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The larger plants given above reappear almost everywhere. 
In many places the thickets are formed by Tamarisks alone. 
Thus flat banks of clay left by the river may be covered 
uniformly by small plants of Tamarisks about 0,;—0,; metres 
high. These uniform thickets are partly artificial as they are 
cut down close to the ground every third or fourth year and 
taken away for firewood. 
In the true thicket the Tamarisks attain a height of about 
3 metres. There are two species (perhaps more, as Lirwinow 
has in recent years described a number of species): Tamarix 
Fig. 18. Growth of Erianthus Ravennae in the river-valley of Amu Darya 
at Chasarasp. In the foreground, scrub of Lycium and Tamarisks. August. 
hispida with its somewhat bluish green foliage and T. laæa a 
glabrous species. T. elongata is also met with here. 
Erianthus Ravennae is a huge tussock-grass, with grey 
hairy tops rising 4—5 metres above the ground, and long 
narrow leaves bent outwards in all directions. This plant 
sometimes forms ‘pure or almost pure thickets (fig. 18), open 
forests of high grass-shoots, but dense enough below amongst 
the huge tussocks with their long leaves. On the ground 
