[Illustration: LOWER KAMA-CHU.] Crossing over the Jelep La from Sikkim into Tibet in the latter part of May we found the country at 12,000 feet and upwards at the height of spring. The open level spaces were carpeted with a dark purple and yellow primula (_P. gammieana_), a delicate little yellow flower (_Lloydia tibetica_) and many saxifrages. The steep hillsides were ablaze with the flowers of the large rhododendrons (_R. thomsoni_, _R. falconeri_, _R. aucklandi_) and the smaller _Rhododendron campylocarpum_, an almost infinite variety of colours.[18] A descent through woods of pines, oaks and walnuts brought us to the picturesque village of Richengong, in the Chumbi Valley, where we found house-martins nesting under the eaves of the houses. Following up the Ammo Chu, in its lower course between 9,000 and 12,000 feet, we found the valley gay with pink and white spiraeas and cotoneasters, red and white roses, yellow berberis, a fragrant white-flowered bog-myrtle, anemones and white clematis. Dippers, wagtails and the white-capped redstart were the commonest birds along the river-banks. From Yatung we made an excursion of a few miles up the Kambu Valley, and there found a very beautiful Enkianthus (_Enkianthus himalaicus_), a small tree about 15 feet high, with clusters of pink and white flowers; in the autumn the leaves turn to a deep copper red. [18] We marked many of the best-flowering specimens with the intention of collecting their seeds on our return in the autumn. Unfortunately when we came over the Jelep La in October it was in a heavy snowstorm which made collecting impossible. At about 11,000 feet is a level terrace, the plain of Lingmatang, where the stream meanders for two or three miles through a lovely meadow covered in the spring with a tiny pink primula (_P. minutissima_): it looks a perfect trout stream, but what fish there are (_Schizopygopsis stoliczae_) are small and few in number. Between 11,000 and 13,000 feet you ascend through mixed woods of pine, larch, birch and juniper with an undergrowth of rhododendrons and mountain ash. The larches here have a much less formal habit of growth than those of this country, and in the autumn they turn to a brilliant golden colour. The berries of the mountain ash, when ripe, are white and very conspicuous. At this altitude _Rhododendron cinnabarinum_ reaches its best growth, in bushes of from 8 to 10 feet in height, and the flowers have a very wide range of colour. In the woods hereabouts may often be heard and sometimes seen the blood pheasant, and here lives also--but we did not see it--the Tibetan stag.