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Continuous plant formations of any kind are very rare and 

 are only to be found in the rare places where there is a spring, 

 salt lake or stream. In the open desert scarcely a twentieth of 

 the ground is covered with vegetation and only the toughest 

 species have survived. These are perennials with much more 

 below ground than above, and travellers frequently have to dig 

 them out by the roots to get enough wood for a fire. Annuals 

 are rare except where there is water. 



Fig. 4. There are practically no continuous plant formations in Western 

 Tibet. Bridge over the Indus near Himis. 



The flora of Ladak is richer than that of Tibet, but its affinities 

 are with that country and Turkestan. It is not an old flora, 

 for there are very few indigenous species, and the geologic history 

 indicates that the present great elevation and the present desert 

 flora is very recent. Composites, mints, peas and grasses are 

 probably the commonest, and the following are some of the 

 types that are most in evidence. Ephedra, Echinops, Astragali, 

 Capparis spinosa, Christolea crassifolia, Pediailaris tuhiflora, 

 Peganum Harmala, Eufotia, Caragana, wild rhubarb and peren- 

 nial potentillas. 



Although the flora is not rich, it is a very interesting one, as 

 it shows the ability of plants to adapt themselves to the most 



