GEOGRAPHICAL BOTANY. 365 



Jhelum, or of the salt-chain, which is intersected by in- 

 numerable offsets of the Himalaya and Soliman moun- 

 tains, with the exception of the lower fluviatile valleys, is 

 free from all those Indian vegetable forms which, up to 

 the foot of these mountains, are extended in an uninter- 

 rupted distribution over the Punjab. 



But Royle's investigation passes over unnoticed a still 

 more important aspect of the question regarding the 

 boundaries of the Indian flora. Hitherto we have only 

 treated of tropical forms of vegetation, to the growth of 

 which the rainy season is unfavorable ,- but in addition to 

 these, India possesses in the Himalaya and the monsoon 

 region that mountain vegetation also, in which the European 

 type is repeated, Here the question arises whether the 

 areal limits of the latter are the same as those of the 

 former, with which, in fact, they partly grow in common 

 on the western chain of the British Himalaya, without, 

 however, being favoured in the same degree, during their 

 period of vegetation, by the tropical rain. The knowledge 

 of this remarkable coexistence of the productions of two 

 climates, for which we are also principally indebted to 

 Royle's former investigations, has not induced him to 

 devote his attention to the question of whether there are 

 not forests of Himalayan trees in other regions which do 

 not shade tropical plants in the rainy season. However, 

 the simultaneous publication of Jacquemont's Journal at 

 Cashmere has thrown some light upon this obscure point 

 (Voyage dans 1'Inde, vol. iii, p. 169). The traveller 

 describes his journey from the Punjab to Cashmere over 

 the Pirpanjol, the Himalayan Pass, which Royle, relying 

 upon Bernier's descriptions, had formerly marked as a 

 sharply-defined limit of the vegetation of the Indian 

 flora, which assertion he now himself withdraws pretty 

 openly. During the ascent, the pomegranate and olive 

 trees disappeared at an elevation of 16 1700m., and 

 soon after, Pinus longifolia also. A region of oaks, 

 Pinus attenuata, and firs was next met with, which, on 

 the northern slope of the chain, extended above the level of 



