are 
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 südrussischen Steppen” 
(1906), the difference between desert and steppe is again em- 
phasized. 
The Russian memoir by A. RopsewircH: “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, Aeluropus 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 of 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 
