45 



The river banks are occupied by poplars and immense tufts 

 of grass (Erianthus). 



East of the Amu Darya we are on the desert of shifting 

 sand again, and then the large oasis of Buchara is reached. 

 The sun is shining on green fields, tall poplars and brown 

 clay houses. This is our first camping place. 



During these past days we have while traversing them 

 acquired a preliminary knowledge of three of the greater 

 plant formations of Transcaspia, namely the Clay-desert, the 

 Sand-desert and the Riverside Thickets. The first we have seen 

 in its luxuriant spring aspect characterized mainly by short- 

 lived annuals; the second, seen at its worst, is distinguished 

 by the exceptionally severe conditions under which only a 

 few, specially equipped plants are able to live; the third is a 

 fringing or gallery-forest ("Galleriewald") rigidly limited to 

 the banks of the river. 



It is the object of this contribution to describe these and 

 other formations more closely. First, however, it will be 

 necessary to consider the plant-formations of Transcaspia re- 

 cognised by earlier writers and to explain our choice of 

 names used to designate the formations in the following 

 pages: 



In the Caspian Depression-territory - - extending from 

 the southern limit of the forest in European Russia to the 

 Caucasus and the border-mountains of Persia , GRISEBACH 

 recognises three formations, namely Grass-steppe, Sand-steppe 

 and Salt- steppe (I p. 455). The first of these has a soil with 

 humus and is the south Russian steppe which does not come 

 within the scope of this work. Under Salt-steppe he records 

 a series of other "formations" (p. 461) between which, how- 

 ever, he does not distinguish sharply. The following three 

 are noteworthy: 1) Dry Clay-steppe with a few Saxauls, an- 

 nual Chenopodiaceae or Artemisia fragrans or Anabasis aphylla, 

 2) More moist steppe with bushes of social Salsolaceae and 

 Tamarisks, 3) Salt-swamps. 



BORSZCZOW distinguishes 3 u areas" (see p. 24), namely 

 Salt-desert, Clay-desert and Moving-sand-desert besides two, 

 which lie outside our area. Finally ANTONOW has in ad- 

 dition to " Mountain-Flora", five formations namely Loess- 



