TORREYA 



December, 1915. 

 Vol. 15 No. 12 



SOME OBSERVATIONS ON THE FLORA OF THE 

 NORTHWEST HIMALAYA 



By Ralph R. Stewart 



During three years' service in an American college in the 

 northern part of the Punjab I found time to spend two summers 

 travelling in the northwest Himalaya and western Tibet. This 

 part of the mountains is much drier than that further east in 

 Nepal, Sikkim and Assam, where the mean rainfall is over 120 

 inches a year, and the flora is rich in types from western Asia 

 while in the eastern Himalaya there is a large endemic and 

 Chinese element that does not get much west of Simla. Al- 

 though I travelled about 2,000 miles in the mountains, mostly 

 on foot, I did not go west of Simla and most of my botanical 

 observations are from the valleys of the Jhelam and Upper Indus. 



Drude, following Brandis, classified the vegetation of the 

 Himalayas altitudinally into four main regions: (i) an Alpine 

 belt; (2) a temperate forest belt; (3) a subtropical forest belt; 

 (4) a tropical forest belt. As one goes northwest the last two 

 belts become narrower and narrower until at Rawalpindi, near 

 the Afghan frontier, the tropical belt has disappeared and a 

 narrow belt of low scrub is all that remains of the subtropical 

 forest. 



This gradual change is correlated with the decreasing effects 

 of the monsoon, due largely to the distance from the sea. In the 

 popular mind India is all a tropical country with palm trees, and 

 tigers looking out of the jungles. In reality one sees practically 

 no picture-book jungle and what is called jungle by the natives 

 is an uncultivated bit which is covered with prickly scrub and 

 [No. II, Vol. 15, of ToRREYA, Comprising pp. 233-250, was issued 19 November, 



1915] 



251 



