364 GEOGRAPHICAL BOTANY. 



Even from Attock, according to Elphinstone (Cabul, p. 

 130), the tropical rains extend northwards as far as 

 Hindu-Rusch, without the high flats of Afghanistan being 

 moistened by them; for Surat would there form its 

 western boundary, at which place, in summer, whilst e. g. 

 rain still falls in Pukkely, the sky is overcast for a month 

 only, and merely occasional showers fall. Thus the 

 double harvests of the Indian year, which are occasioned 

 by the rainy season, cannot be obtained west of Jellalabad 

 (Irvine, Journal of As. Soc. of Bengal). Hence between 

 Jellalabad and Gundamuc, on the road to Cabul, the 

 periods of development of the vegetation are suddenly 

 changed. " In Gundamuc," writes Burnes, " the willows 

 flowered at the end of February. On the llth of March 

 the first spring flower appeared ; it was a sweet-smelling 

 Iris. The apricots began to unfold their buds on the 1st 

 of April; the wheat here was three inches above the 

 ground, whilst in Jellalabad it was already cut." But when 

 we take into consideration the elevation of the soil above 

 the Indus and its tributary streams, it appears clear that 

 the tropical conditions of the vegetation only extend so 

 far west in the valleys. In fact, Royle does not allude to 

 the important question, to what elevation the mountain- 

 slopes which limit these fluviatile valleys on every side are 

 reached by tropical rains ; but as regards Cashmere, a 

 valley lying far to the east of Peshawar, we know that the 

 atmospheric precipitations of the spring cease to occur at 

 that period at which the rainy season commences in the 

 Indian plains and the low valleys of the Himalaya. Thus 

 it appears, from all the descriptions, that the more elevated 

 regions in the neighbourhood of Attock and Peshawar 

 are not subjected to the monsoon. This explains Elphin- 

 stone's statement, that a number of English plants thrive 

 in the gardens at Cohaut, where plum arid peach trees 

 were in flower at the end of February, and where weep- 

 ing willows, plane, and apple trees were thriving upon 

 European meadow plains. From these reports, it is pro- 

 bable that the entire district west and north of the 



