43 



between the lower course of Syr Darya, the river Tshu, the 

 northern shore of Lake Balchash and the upper Irtish. 



The Stipa-steppe and the Clay-desert have already been 

 referred to in our summary of BORSZCZOW'S memoir which is 

 also followed by TANFILJEW. 



4. The Sand-Deserts in Transcaspia are described as by 

 BORSZCZOW and KORSHINSKY. 



In TANFILJEWS treatise: "Die siidrussischen Steppen" 

 (1906), the difference between desert and steppe is again em- 

 phasized. 



The Russian memoir by A. RODSEWITCH: "The Tree-Ve- 

 getation of Transcaspia" (1896), is known to me only through 

 a summary by LIPSKY in "Contributions from the Botanical 

 Garden in Tiflis", 1902. 



Of about 500 species found in Transcaspia, nearly half 

 belong to the desert-flora; of these 17 per ct. are trees and 

 57 per ct. perennials. The characteristics of the desert-plants 

 are: a strongly developed root-system, sclerenchyma in the 

 stems, the radical branches encased in a siliceous coat, and 

 the leaves poorly developed. The most important sand-plants 

 are: Haloxylon Ammodendron, Tamarix gallica (?), Alhagi ca- 

 melorum, Aeluropiis repens, Salsola subaphylla, Populus diversi- 

 folia (euphratica), Ephedra, Eremosparton aphyllum, Aristida 

 pungens var. pennata, Ammodendron Karelini, Calligonum and 

 Salsola Arbuscula. 



So far as I know these are all the available memoirs 

 which deal with the vegetation of the Transcaspian lowlands. 

 If all have not been included, I hope that nothing ot great 

 importance is left out. Descriptions in general works on 

 plant-geography have been omitted since they must ne- 

 cessarily be compiled from the original works. 



CHAPTER 5. 



Classification of Formations. 



On a lovely sunny day in April 1898 the expedition saw 

 the . brown mountains of Asia rising above the Caspian Sea. 

 The mountains near Krasnowodsk on the eastern shore of 



