ar == 
ous stones makes the soil still more unfavourable to vege- 
tation because the stones retard the absorption of water, 
reduce the capillarity and promote the conduction of heat in 
the soil. On the other hand they act favourably by reducing 
the evaporation from the surface (RAMANN). 
The vegetation will only be described for the more im- 
portant localities I have seen (all with one exception in 
summer). 
At the base of Sultan Uis Dagh, an isolated group of 
mountains near Chiwa (see map), I examined a desert strewn 
with loose pieces of slate, and dotted here and there with 
rocks in situ. This desert evidently corresponds to what 
VOLKENS calls “Kieselwüste” WALTHER and MIDDENDORFF call 
“Kieswtste’. As in Egypt, so the desert here was almost 
devoid of plants. Only in depressions and where the number 
of stones seemed to be less, did various low undershrubs and 
dwarf-bushes occur: Salsola rigida, Artemisia herba alba, 
Capparis spinosa, Atraphaxis compacta and Haloxylon Am- 
modendron, the latter being low shrubs about half a metre 
high. Less conspicuous were Stellera Lessertü, Convolvulus 
fruticosus, along with Halimocnemis macranthera and Anabasis 
eriopoda, two pronounced halophytes. In Ferghana, MIDDEN- 
DORFF found about one plant per square foot (l. c. p. 21) on 
the stone-desert. 
The mountain itself, Sultan Uis Dagh (Sultan Baba-ne 
Dagh-e) consists of nearly vertical strata of a greenish clay- 
mica-slate, often impregnated with quartz. The surface in 
many places is covered by disintegrated matter, fine yellow 
clay and pieces of slate with a shiny tawny weathered sur- 
face. Everywhere was very dry, even the deserted beds of 
several streams, which were no richer in vegetation than the 
rest. The following plants were found scattered widely about: 
Atraphaxis compacta, Salsola Arbuscula, Salsola rigida, Cap- 
paris spinosa, Artemisia sp., all dwarf or undershrubs, also 
two withered annuals, a Composite and Lepidium persicum (?) 
and low trees of Saxaul less than a metre high. 
At Kis-Kalä, a mountain with a ruined castle, on the 
right bank of the Amu Darya more to the south, I saw a 
desert where the soil consisted of very stony gravel and sand. 
