DE ie 
But when it grows in the moving-sand desert, it becomes a 
small tree, more than 4 metres high, and with long, pliant 
shoots and leaves (comp. fig. 12 and fig. 38). The foliage is 
comparatively rich; it is a green tree sufficiently dense to 
cast a shade. 
The plant is very hardy and can endure being covered 
by sand, a process which only hastens its already precocious 
growth, and (according to PALEZKIJ) roots are formed from 
the buried parts of the stem. He also states that he has 
measured roots 15 metres in length, many of them horizon- 
tal. Whether suckers are formed from them I do not know. 
I have seen a tree from which the sand had been blown 
away, so that it had fallen and lay on the slope of a dune 
with some of the branches buried. The plant, however, was 
perfectly fresh, still fixed by its roots and it had given off 
new roots from the buried branches. 
Salsola subaphylla is somewhat similar in appearance, 
but has coarser and less dense foliage and neither in height 
nor age does it come up the other species. Somewhat saline 
soil is the most favourable for this plant. 
Both species blossom freely in the late summer and in 
September they bear large clusters of broad-winged perianths 
carrying the fruits. 
These two species, particularly the former, play an im- 
portant part in the operations for binding the sand along the 
railways. 
Calligonum (figures 11, 27, 28) and Eremosparton aphyl- 
lum (figures 23, 24) are both leafless i. e. the leaves are re- 
duced to quite small scales, and both are shrubs or small 
trees attaining a height of about 4 metres. They have long 
roots (PALEzKIJ measured roots of 4,25 metres in a year-old 
specimen of Calligonum Caput Medusae) and both plants can 
form root-suckers. 
They are both sand-plants — Calligonum, however, not ex- 
clusively — and they endure the sand-drift very well. Of the 
many species of Calligonum (see list in chap. 12), C. Caput 
Medusae is the most important. It flowers in May or June 
and already in June one finds the curious globular reddish 
fruits set along the slender twigs. The fruits are achenes 
