25G Capt. Pembertoris Mission to Bootan, 1837-38. [April, 



consisting of herbaceous plants, whose growth is confined to a very 

 few congenial months, and which were almost all hid from my view 

 by the heavy snow, so constant between the latter end of October and 

 the commencement of May. Another striking feature in Bootan is the 

 constancy with which southern faces of mountains are, especially 

 towards their summits, bare of trees or shrubs ; this it has in 

 common with other parts of the Himalayas both to the westward, 

 where it has struck all travellers, and to the eastward, as on the 

 Mishmees. I am not prepared to state whether any satisfactory 

 explanation of this has been given ; it struck me to be due, in 

 Bootan at least, to the searching severity of the winds, which are 

 quite sufficient to keep down all luxuriance of vegetation. Whatever 

 the secondary causes may be, there can be no doubt that the primary 

 one is due to the influence of the south-west monsoon, to which all 

 these faces of the Himalayan mountains are freely exposed. 



The higher the altitude the greater, as indeed might be expected, 

 was the uniformity of vegetation, and it was only in such that any 

 general features of vegetation could be said to occur. A very constant 

 feature of high altitude, such as from 11,000 to 12,500 feet, existed in 

 the black fir, a lofty tabuJarly branched tree of a very peculiar 

 appearance, in comparison at least with other Bootan species, and 

 which, when seen standing out in dark relief, might, from the very 

 frequent mutilation of its lower branches, be mistaken at a distance for 

 palm; with these there was as nearly a constant association of the 

 same species of other plants. The most striking among the partial 

 features of the vegetation of Bootan was presented to us by the three 

 valleys, so often alluded to ; these may well be called the region 

 of pines of that country. The range of the three species was most 

 distinct and very instructive, although the Smithian Pine, a little 

 further to the westward, descended to a somewhat lower elevation than 

 it did in the tract above mentioned. 



Still more partial features were presented by the Pinus excelsa, and 

 more especially by the Pinus longifolia, the distribution of both of which 

 appears to depend on local causes. The latter species was not seen 

 on our return, nor was tiiere a vestige of a fir visible after reaching 

 Chuka ; no species but the long-leaved was seen below 5500 feet. 



I have in the foregoing few remarks merely glanced at the most 

 familiar features of the botany of Bootan. As the importance of strict 

 determination has been much insisted on before correct views can be 

 formed of the botanical geography of any country, I have purposely 

 omitted all details, until the collection shall have been duly examined; 

 but even when this has been done, the difficulties arc almost insuper- 



