TO THIBET. 99 
extend. A Lichen grew at the very top; but the highest phanero- 
gamous plant which came under my notice, was a small Composita, 
the Pyrethrum roseum of Jacquemont’s Journal, which inhabited 
the crevices of rocks, at an elevation of 17,500 feet. Though 
disappointed by the sterility of the southern side of the Pass, 
I gathered several alpine species, when descending the northern 
slope and following the course of the river. The loftiest part 
certainly promised ill enough: a mile and a half of snow was 
followed by an equal length of glacier. The mountain vegetation 
is quite different from that of the ordinary level of the country ; 
or, to speak more definitely, the plants of 16—17,000 feet are by 
no means the same as those of 14—15,000 feet. Elevation is, 
however, not the sole cause which influences vegetation : exposure 
and distance from the bottom of the valley have a marked effect. 
Thus Biebersteinia odora occurred on the Roonung Pass in Kunawur, 
at 14,200 feet, and was plentiful on the descent of the Parang Pass ; 
but below 15,000 it disappeared, and though we have since con- 
tinued at between 14 and 15,000 feet, I have not met with it 
again. The Biebersteinia, a minute Astragalus, a Lychnis and 
two Grasses, were the first plants which greeted me on the descent, 
appearing just where the glacier terminated, and they were soon 
followed by a Mepeta, four species of Potentilla, a Fern, a 
Gnaphalium, and a couple of Carices. By the way, the Potentilla 
have been a particularly numerous tribe since I entered Kunawur; 
I think I have collected not less than twenty. | 
Our encampment below the Parang Pass was at above 16, 000 
feet, and our lowest elevation before leaving that stream, was : 
14,000 feet, so that we very gradually diminished our altitude in 
three days, which gave me a good opportunity of noting the . 
appearance and disappearance of different plants. The former is —— 
an easy task; the latter not only difficult but impossible to be 
accurately Fn by persons who are rapidly traversing a new region; — 
so, as my notes are still quite rough, and the changes of vegetation — 
very frequent, I prefer a that point alone, for the present. - 
I have already stated that the alpine species vanish above 15,000 
feet. Aog tha bankai my and in eod bent minim 
