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occurring within the territory defined in chap. 1, but also 

 species which likewise occur in the Balchash-basin, with 

 natural conditions which to my knowledge are almost ident- 

 ical with those of Transcaspia and without transition. Dsung- 

 aria, on the contrary, is left out, and species which are also 

 found there are classed under those with an eastern distri- 

 bution (denoted H). In my opinion this was necessary, 

 firstly in order to fix a boundary between the eastern and 

 the endemic species; secondly because Dsungaria, though 

 much the same in character as the Balchash-basin, yet for 

 the greater part lies higher and according to BUNGE (1880, 

 No. 26) it also differs to some extent in phytogeographical 

 respects from the countries lying to the west. 



Nor are plants occurring in the areas north of the Aral 

 Sea regarded as endemic. It is impossible to fix any natural 

 well-defined boundary between Transcaspia in the south and 

 the Kirghiz-steppe in the north, but the boundary I have 

 selected, the 46 th northern parallel of latitude, cannot be far 

 wrong as it is confirmed in the recently published work by 

 SAWITCH. This memoir shows that several plants which are 

 common in Central Europe also occur in the desert north 

 of the Aral Sea (see p. 5). 



The census shows that there are 169 endemic species in 

 the Transcaspian lowlands, that is 22 p. cent, of the total 

 number of species. If the area had been differently defined 

 so as to be wider in extent and to include for instance the 

 the w r hole of West-Turkestan inclusive of the mountains, it 

 is possible that the endemic percentage might be increased, 

 but then it could not be regarded as an expression of, or to 

 be connected with, the homogeneous natural conditions which 

 pervade and have pervaded the Transcaspian lowlands. Since 

 the area has been confined within such narrow limits, we 

 must have a certain right to see such a connection, remem- 

 bering, however, that the endemism is dependent not only 

 on the number of species formed, but also on the faculty of 

 migration and adaptation of these species. The endemism 

 would have been still greater if the northern boundary of 

 our territory had been moved farther north. If the Kirghiz 

 steppe and the eastern part of Ciscaucasia to the Jergeni 



