53 



leafless or leaf-bearing type, with the exception of Aeluropus, 

 Stalice, Phragmites and the salt-excreting Frankenias and Ta- 

 marisks. Their internal structure is dealt with in chapter 13. 



Most of the species are annuals and all are summer- 

 plants, none being ephemeral spring-plants. The annual Sta- 

 tices (S. leptostachya and spicata) are probably not very long- 

 lived, but on this point I have no definite observations. 



As regards the natural development of "Ssor", I can 

 only say that on one occasion I observed that sand from 

 the neighbouring sand-desert had drifted across the salt-flats, 

 and sheltering behind plants of Salicornia had formed mi- 

 niature sand-dunes. If this sand remains long enough it 

 will become permeated by the moisture coming from below, 

 and the salt incrustation must form over it. In this way 

 the surface may be raised a little. This process does not 

 seem, however, to play any great part, because I have always 

 found clay under the salt incrustation, but further examina- 

 tion might perhaps reveal the presence of sand. 



That the barrenness of the salt-desert is due to the want 

 of fresh water alone, was illustrated by a striking example 

 seen near Buchara. Here in May 1898, two parallel ditches 

 were dug through a snow-white salt-desert, and the excavated 

 material was made into a mound between them, so that the 

 mound and the double ditch surrounded a square piece of 

 of ground. The inner ditch was connected by a long straight 

 ditch with the irrigation system of some tilled fields in the 

 neighbourhood. The piece of ground enclosed by the mound 

 and the ditches was perfectly green, Aeluropus littoralis having 

 spread so luxuriantly that it almost formed a carpet of 

 vegetation and so dense that it almost suppressed all the 

 other halophytes, only a very few Halostachys being left. 



Outside the outer ditch the ground was white with salt 

 and covered with scattered Halostachys caspica and Aeluropus 

 (fig. 3). 



The peasants told me that the enclosed piece of ground 

 was made into a field this year, that it had only once been 

 irrigated (through the long straight ditch) and that in the 

 autumn they intended to sow it with wheat. MIDDENDORFF, 



