ER GI es 
These observations indicate that the vegetation of the 
Stone-deserts is mainly characterised by xerophytic stunted 
shrubs and undershrubs. Whether spring-plants occur there, 
I cannot say. 
The following are species found only in the Stone-desert: 
Convolvulus fruticosus, Stellera Lessertii, Reaumuria fruticosa 
and Atraphaxis compacta, all dwarf-bushes or undershrubs 
with small and flat leaves. The following seem to be common 
in the Stone-desert, though they also occur in other forma- 
tions: Reaumuria oxiana, Salsola rigida, (one of the most 
frequent) Arthrophytum subulifolium, Artemisia sp., Convolvulus 
eremophilus, Capparis spinosa. 
CHAPTER 9 
The Formation of the Sand-Deserts. 
The soil of this formation is sand, at least on the surface. 
The sand varies in origin and age as stated in chap. 2'), but 
these differences do not seem to play any essential part with 
respect to the vegetation (KorsHinsky p. 8). The different 
aspects presented by the sand are of greater interest to the 
botanist. These have been described by MusHKETOW, RADDE 
and SEMENOW, and the following survey of the various sand- 
landscapes is based on the observations of these authors. 
1. Barchans, crescent-shaped, dirty yellowish or fawn- 
coloured dunes of inland sand. MuskErow states that they 
are generally 30—40 feet (ab. 9—12 metres) high, and 
may attain a height of a hundred feet (ab. 30 metres); SE- 
MENOW gives 40 metres but I have rarely seen any higher 
than 10 metres and RappE gives 30—35 feet (ab. 9—10 metres) 
as the maximum. The sand-grains are rather small. RADDE 
(1899, p. 16) gives 0.2—0.3 m. m. as the average size for 
Barchan-sand and Sand-steppe sand from Amu Darya and Kara 
1) See moreover RoMANOWSKI p. 52. 
