INTRODUCTORY ESSAY. 193 



valley, Acacia modesta, Zizyphus Lotus, and a spiny Celastrns, 

 which west of the Jelam form the great mass of the tropical 

 vegetation. Of tropical fruits^ the orange and plantain are 

 cultivated in all the hot valleys of the Panjab Himalaya; and 

 the mango extends to the Indus, and perhaps beyond it. The 

 pomegranate, both wild and cultivated, is abundant in the sub- 

 tropical jungles, even as far west as Lower Kishtwar. 



In the temperate zone of the outer Western Himalaya, the 

 commonest trees of the drier exposures are Rhododendron ar- 

 boreum, Andromeda ovalifolia, Quercus incana and dilatata; 

 and the prevailing shrubs are species of Berberis, Rosa, Spi- 

 r<ea, Rubus. All of these occur throughout the whole of the 

 chain from Kumaon to the Indus, but to the westward they 

 seem restricted within gradually narrower limits, and in the 

 extreme west are found only in moist and shady woods, which 

 in Kumaon and Garhwal they carefully avoid. To the east- 

 ward they are accompanied by many other trees which gra- 

 dually disappear : thus Quercus lanata and Betula cylindro- 

 stachya are not found west of the Ganges, and Carpinus vi- 

 minea has not been observed west of the Satlej. 



In the valleys of the temperate zone and on the lower 

 slopes of the hills the forest is usually very different : Celtis, 

 Alnus, Populus ciliata, Prunus Padus, ASsculus, and two spe- 

 cies of Acer are common trees as far west as the Jelam, or 

 perhaps the Indus. Most of them indeed seem to occur in 

 the humid forests of the Hindu Kush, north of Jelalabad. 

 Benthamia floribunda and a Hydrangea extend from the East- 

 ern Himalaya as far as the Satlej, but have not been found 

 further west, and many species of Lauraceae advance to the 

 Indus. 



The influence of climate is much more perceptible on the 

 herbaceous vegetation of the temperate region, and especially 

 on the annual plants which spring up during the rainy season, 

 than on the trees and larger shrubs, which may be presumed 

 to have greater powers of resistance. Hence the Scitaminece, 

 epiphytical and terrestrial Orchidea, Aracea, Cyrtandracea, 



2 c 



