S,22 FLORA INDICA. 



mountains round the Pangong lake, and Captain Richard 

 Strachey and Mr. Winterbottom a very valuable one in Guge 

 in the autumn of 1849. Mr. Lance has also sent us, through 

 Mr. Edgeworth, a collection from Piti, Ladak, and Dras, which 

 contains many interesting species. 



Our attempts to divide Western Tibet into provinces have 

 been attended with unusual difficulty, owing to the undefined 

 limits of those already established, and to the fact that the 

 natives of that country have no system of nomenclature for 

 large areas, mountain chains, or rivers, available for our pur- 

 pose. Considering how scanty the flora of Western Tibet is, 

 not amounting perhaps to more than 500 species, and how 

 widely the majority of these are spread, any division into 

 provinces might perhaps have been dispensed with, — so far 

 as the purposes of geographical distribution are concerned; 

 but the flora of the country is far too imperfectly known in 

 detail to warrant the assumption that particular habitats are 

 wholly useless; and we should further be depriving future 

 local botanists of the benefit of our local knowledge. 



In the following attempt we have been guided wholly by 

 the river systems, which enable us to divide the country 

 into three parallel lines of provinces, that occupy (within 

 rough limits) — 1. The north slope of the Himalaya; 2. The 

 beds of the Indus and Satlej ; 3. The south slope of the 

 Kouenlun : they are as follows : — 



1. Guge, the Tibetan course of the Satlej. 



2. Piti and Parang, the basins of the rivers of those names, 

 tributaries of the Satlej. 



3. Zanskar, the basin of the Zanskar river. 



4. Dras, the basin of the Dras river. 



5. Nari, the upper course of the Indus. 



6. Ladak, the middle Tibetan course of the Indus. 



7. Balti, the lower Tibetan course of the Indus and of the 

 Shayuk rivers. 



8. Nubra, the upper basins of the Nubra and Shayuk rivers, 

 tributaries of the Indus, 



