THE 
NEW PNYTOLOGIST. 
Vol. XI, No. 9 . 
November, 1912. 
[Published Dec. 5th, 1912]. 
ON THE ALTITUDINAL LIMITS OF PLANTS IN 
NORTH-WEST YUNNAN. 
By F. Kingdon Ward, B.A., F.R.G.S. 
[With Plates VII and VIII, 
and a Map and Section in the Text]. 
N observant traveller mountaineering in N.W. Yunnan must 
inevitably be struck by the apparently capricious manner in 
which the vegetation changes its character, or ceases abruptly, now 
at one altitude, now at another. These transitions, however, do not 
really take place in the whimsical manner which at first sight 
appears, and in the following notes I will endeavour to point out 
some of the controlling factors which seem to me of chief importance 
in determining the formations, particularly as regards the extreme 
limits of flowering plants in these mountains. 
My observations, being very incomplete, are necessarily sup¬ 
plemented by several suggestions which will doubtless be more or 
less open to criticism amongst those who have studied these 
problems. 
The peculiar topographical features of the country favour 
peculiar climatic conditions, which, owing to the great variations of 
altitude condensed into a comparatively small area, exhibit both 
a wide range and abrupt transitions. 
The country under review comprises three deep gorge-like 
valleys separated by two narrow mountain-chains, their axes of 
uplift trending north and south, their highest summits rising to an 
altitude of perhaps 23,000 feet; both ridges indeed rise well above 
the snow-line, and in this region exhibit a conspicuous chain of 
snow-clad peaks, though their average altitude is considerably less 
than that indicated (map p. 334). 
