Br 
bearing several series of branches. The vegetative branches 
are annual like the floral ones, and may therefore biologi- 
cally be regarded as leaves which fall off at the end of the 
vegetative period. 
The perennial as well as the annual bragches are often 
closely bunched together owing to the formation of new 
branches year after year at the same place. The younger 
branch-tips are often pendant and wave in the wind (Am- 
modendron, Haloxylon, Salsola Arbuscula). 
They have all long roots. The fruits in every case con- 
tain one or at most a few seeds, and are so formed that they 
fly or roll easily before the wind, hence one finds them 
massed together in sheltered places. 
To the bushes and trees given above for the Sand-desert, 
the following may be added which like Saxaul are rather plants 
of clay soils and do not thrive so well on pure deep sand: 
Smirnowia turkestana, Astragalus Ammodendron, paucijugus, 
unifoliatus, Ephedra alata, Tamarisks and probably others. 
The switch-shaped trees and bushes (and Aristida) are 
however rarely the only living plants in the Sand-desert. 
Between the dunes where there is a certain amount of 
shelter, the soil in many places is sufficiently stabilised for 
the growth of hardy herbaceous plants. These are not places 
where there is clay soil between the dunes — such belong to 
the formation of the clay-desert, -- but where there is sandy 
soil somewhat sheltered and therefore not shifting. Here grow 
a number of annual and perennial herbs which are more 
xerophytic and less halophytic in type than the clay-plants. 
They occur scattered about, and frequently they have a hard 
struggle for existence where the sand blows away or drifts 
over them. 
One of the most frequent is Heliotropium Radula. This 
like H. sogdianum which also occurs, has a thin horizontal 
rhizome, sometimes of considerable length (2,5 metres and 
more), and lying close under the sand-surface; it puts forth 
numerous aerial shoots, which generally form hairy leaf- 
rosettes arranged in a row, similar to the rosettes of our Carex 
arenaria. (Fig. 63). Long-jointed shoots bearing inflorescences 
