I spent a considerable time on the top of the pass, and by close searching, in the crevices of the stones, especially on the hill which rose to the south-east, I succeeded in collecting a considerable number of species of plants, though very much fewer than on the Werang pass two days before. From our morning's camp to the top of the pass the whole number of species which I met with was only forty-six, not half of which were observed on the summit. The number gathered on the former pass was nearly three times as great. It must not be forgotten, however, in comparing the two ranges, that the Werang pass is 1300 feet lower than that of Runang, and ought therefore, independent of climate, to be more productive. The species which were observed for the first time on the summit of the Runang pass were not more than six, and were all forms which I have since found to be abundant throughout the higher parts of Tibet. A little willow, creeping among the stones, and scarcely more luxuriant than _Salix herbacea_, was the only shrubby plant. The others were _Oxytropis chiliophylla_, _Biebersteinia odora_, a _Draba_, _Lamium rhomboideum_ of Bentham, and a species of rhubarb, of which I found only a few leaves and one or two panicles, from which the ripe fruit had nearly fallen away.
The descent from the pass to Sungnam was even more barren and desolate than the other side. The valley was open and almost straight, and the slope gradual. Till nearly half-way not a drop of water occurred on the road, and for miles almost the only vegetation on the hill-sides was an erect branched _Polygonum_, never more than a foot in height. At an elevation of about 10,000 feet, a few deodars occurred, all miserably stunted in height, though often with trunks of considerable diameter. Gerard's pine, and the ash of Tibet, also appeared a little lower, but in very small numbers. During the greater part of the descent, the white houses of Sungnam were in sight, to all appearance at the end of the valley down which we were proceeding; but when near the bottom, we discovered that we were still separated from them by a wide and level plain, that of the Ruskalan river. On the opposite side of this plain, on the side of a hill just sufficiently high to terminate the vista down the valley by which we descended from the pass, stands the town of Sungnam; while the cultivated lands, which form a wide belt, scarcely higher than the level of the river, were entirely out of sight till we arrived close to the precipitous bank parallel to the river. Here the descent was abrupt to the bed of the Ruskalan. The bank was alluvial, with enormous boulders, and was covered with tufts of _Ephedra_, a remarkable leafless plant with rod-like branches, which is abundant in every part of northern Tibet, especially in the driest and hottest exposures. It extends also occasionally into the partially rainy district, being found in Kunawar nearly as far west as the bridge of Wangtu.