| Mean temperature | 59° | Fahr. |
| Mean minimum at night | 52 | |
| Highest temperature observed | 67 | |
| Lowest temperature observed | 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.
The shrub-Calisayas, which were growing plentifully by the roadside, above the valley of Sandia, were entirely exposed, without any shade whatever, and the hill on which they grew had a western aspect. There is a difference in elevation of about 1000 feet between the locality where we saw the shrub-Calisayas, and the region of the normal tree-Calisaya in the Tambopata forests; and the shrubby form is also many leagues nearer the snows of the cordillera. These circumstances are alone sufficient to account for the difference in the habit of these two forms of C. Calisaya; and there seems to be no doubt that the barks of the shrubby varieties of chinchonæ are specially good when their stunted growth is owing to the altitude of the locality.
Our collection of chinchona-plants in the Tambopata forests, and on the pajonales, was completed on May 14th, as follows:—
| No. of Plants. | |
| C. Calisaya (calisaya fina) | 237 |
| C. Boliviana (calisaya morada) | 185 |
| C. ovata, var. α vulgaris (zamba ordinaria) | 9 |
| C. ovata, var. β rufinervis (zamba morada) | 16 |
| C. micrantha (verde paltaya) | 7 |
| C. Calisaya, var. β Josephiana (ychu cascarilla) | 75 |
| Total | 529 |
CHAPTER XVII.
JOURNEY FROM THE FORESTS OF TAMBOPATA TO THE PORT OF ISLAY.