A BOTANICAL TOUR IN SIKKIM. 213 



Of trees which do not extend above 10,500 feet in this valley, are Picea 

 Morinda, Tsuga Brunoniana , Larix Griffitliii, Prunus Padus, Pyrus lanatus, 

 Pyrus sihkimensis , Hydrangea, Ilex dipyrena. Above this elevation to 13,000 

 feet is a continuous forest of Abies Webbiana associated with Maples, Birch, 

 Viburnum, Berberis, and Rhododendron ; Aconitum Napellus grows luxuriantly 

 on the grazing ground at Sebu. 



At 11,000 feet large trees of Juniperus recurvus appear, and at 13,000 feet 

 (the upper limit of Abies Webbiana) and for a short distance above it they 

 form the only arboreal vegetation. 



From 13 to 15,000 feet there is an impenetrable growth of Rhododendrons 

 and Willows, with numerous small trees of Pyrus foliolosa, and P. microphylla; 

 and, intermingled with grass underneath these bushes, is an equal luxuriance of 

 herbs, such as Aconites, Senecios, Saxifrages, Primulas, Potentillas, Polygonums 

 and Thistles. Cnicus eriophoroides , which is moderately common in most 

 valleys, is so abundant here as to be a perfect pest. 



From Sebu (12,500 feet) the next march was to a yak-grazing station, named 

 Sethang, at an elevation of about 15,000 feet. Up to 14,000 feet the floor of 

 the valley is very steep, but about 1,000 feet below the level of Sethang we 

 emerged on a swampy flat, through which the Sebu flows in several channels. 

 Its surface is covered with grass, and its borders are cumbered with Rhododen- 

 dron Anihopogon. A tributary from the west pours over the hollow of a preci- 

 pice in a magnificient waterfall. Above the plain is a steep rocky barrier 

 thrown transversely across the vallsy. On reaching its summit we arrived at 

 the camping ground. The coolies took up their quarters in the deserted huts, 

 and my tent was pitched near an accumulation of enormous boulders, A small 

 muddy pond lies at the upper end of the flat. 



Here the two branches of the river Sebu unite — one rising in Donkia, the 

 other in the nameless snowy mass south of Ghora La. The former is seen 

 flowing in a deep and narrow gorge ; the latter rushes down a steep rocky trans- 

 verse slope similar to that which we ascended below Sethang. These slopes 

 run parallel to each other, and are probably the terminal moraines of the 

 glacier, which is now confined to the head of the valley. Rhodedendron com- 

 panulatum is the common shrub. Primula Stuartii, Meconopsis nepalensis, 

 Geranium collinum, all in fruit, abound on the flat. 



On the following morning I walked to Ghora La, elevation 17,000 feet. The 

 path descended into the stream from the Donkia, the ascent beyond winding 

 amongst gigantic boulders on the western side of the slope. At the top is 

 another small plain, and the remaining portion of the valley becomes broader 

 and ascends by a long easy gradient to 16,500 feet. 



The valley from this point onwards to near its head is bounded by even 

 ridges and unbroken slopes which are possibly the lateral moraines of the 

 ancient glacier terminating below Sethang. 



Both seemed to be elevated 500 feet above the river. A broad terrace runs 

 along the base of the eastern one for some distance. Higher up, the valley 



