Above the zone of the _C. ovatas_, and nearer the snowy cordillera (for lower down the valley the forests cover the crests of the mountains), commence the open grassy _pajonales_, which I have already described. Here the formation is exactly the same as that in the valley of Tambopata; and the vegetation of the thickets which fill the gullies, and are interspersed over the grassy glades, consists of _huaturus_, _Gaultheriæ_, _Vacciniæ_, _Lasiandræ_, and other _Melastomaceæ_, _Chinchonæ_, palms, and tree-ferns. The chinchonæ consist of _C. Caravayensis_, and of the shrubby variety of _C. Calisaya_, which is called _ychu cascarilla_ by the natives. The shrub _Calisaya_ (β _Josephiana_) is generally from six and a half to ten feet high, but I met with an individual plant which I believe to belong to this variety, which had attained a height of eighteen and a half feet; and this inclined me to think, at the time, that this shrubby form could not even be considered as a variety of the normal _C. Calisaya_, and that its more lowly habit was merely due to the higher elevation and more rigorous climate in which it grew. Dr. Weddell remarks that its appearance varies very much according to the situation in which it grows, and that the colour and texture of the different parts change according to the amount of exposure. I found the shrub _Calisaya_ in flower in the end of April. We crossed two _pajonal_ regions, one above the valley of Sandia, and the other between the valleys of Sandia and Tambopata. The height of the former above the level of the sea was 5422 feet, and of the latter 5600 feet. The time of my visit was the end of April and beginning of May, and I traversed both regions twice, so that an abstract of my meteorological observations will give a tolerably correct idea of the climate at that time of the year; although they only extend over the 25th, 26th, 27th, and 28th of April, and a few days in the middle of May. Mean temperature 59° Fahr. Mean minimum at night 52 Highest temperature observed 67 Lowest " " 49 Entire range 18 Mean of the dew-point 53.6 (dry bulb as above). In the early morning there were generally masses of white clouds lying in the ravines, and in the afternoon a thick mist drifted across the _pajonal_, with drizzling rain.