590 STEWART: FLORA OF LADAK, WESTERN TIBET 
PLANT ASSOCIATIONS 
From the foregoing we have seen that most of Ladak is covered 
by open desert associations with bare ground between the indi- 
vidual plants. Many hillsides have so little soil and the summer 
heat is so intense that there is scarcely any vegetation at all. 
Sometimes a plant that would otherwise be sure to be eaten off 
can find a refuge beneath a thorny bush of Caragana, but as a 
rule they stand alone or in tufts. 
Occasionally we find a modification of the desert flora. Where 
there is a spring on the mountainside and the water cannot drain 
away readily we get a continuous sod and a typical association of 
Pedicularis longiflora and species of Triglochin, Carex, Gentiana, 
and Taraxacum. The ground is often boggy in such situations 
and the water may be alkaline. 
Alpine meadows are rare except in the transition zone near 
Kashmir. The places along the streams that may have been 
meadows ages ago have been made to grow a few food plants. 
Usually the streams are so swift that they are bounded by steep 
banks and there is very little opportunity for plants to gain a 
foothold or for a sod to form. 
The oases which surround the villages contain practically the 
only trees, and these, with the exception of the Hippophaé, which 
is frequently used for hedges, are practically all introduced. 
commonest trees are willows, poplars, walnuts, mulberries, apples 
and apricots. Small groves of the native juniper, Juniperus macro- 
poda, are sometimes found. The commonest crops are barley, 
wheat and buckwheat. Our common garden vegetables do well 
and so do many of our common garden weeds. 
Although there are no forests in Ladak, there are frequently 
thickets along streams and on little islands in the rivers. These 
have a typical association of the Myricaria, Hippophaé, Rosa and 
Clematis orientalis. These furnish shade for more delicate plants, 
such as species of Veronica and Epilobium. 
