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moisture increases with the altitude. Upon our school-maps 

 great deserts are located on the table lands of this region. The 

 real deserts, however, are not there, but along the coast Upon 

 the highlands there is sufficient moisture to redeem the country 

 from barrenness, and it is a fairly good stock country. As upon 

 the eastern side, so upon the western, the highland vegetation 

 creeps down the mountains as we go southward, until at Val- 

 paraiso it reaches the ocean. North of Valparaiso there is thus 

 left a true desert along the coast, which widens as we go north- 

 ward, until at the boundary of Chili and Peru, we find miles of 

 pure, absolutely barren sand. To the patient and industrious 

 botanist this coast desert will furnish a far more interesting field 

 than the luxuriant regions to the eastward. There is no regular 

 water supply, the showers being infrequent and spasmodic, with 

 years sometimes elapsing between them. But when they do oc- 

 cur in sufficient quantity we find a rich and beautiful flora, 

 springing up, maturing and perishing in an incredibly short 

 period of time. What special provisions are required, and what 

 lessons in physiology are to be learned, while watching the pro- 

 cesses of birth and extinction which are here going on ! Long 

 after the flora of the Amazonian basin shall have been satisfac- 

 torily classified, this desert region Avill be contributing its annual 

 quota of undescribed species. 



With this very meagre general outline before us, we shall 

 notice briefly the special localities where the collections were 

 made. 



A part of a day each were spent at Guayaquil, Zorritos, 

 Payta and Coquimbo, and two or three days at Lima, but only 

 fragments were collected. Zorritos stands at the northern ex- 

 tremity of the desert, and is watered with moderate frequency. 

 The Prosopis, Cereus, Amarantacese and Chenopodiacese, re- 

 niinded me strongly of the gravelly hills of the Mohave desert. 

 Payta is one of the dryest spots in the world, and Coquimbo is 

 but little better. Lima, like Tacna, stands near the foot of the 

 r^ountain. At the latter place a week was spent in the early 

 part of February. No rain had occurred, and the fifty species 

 collected were all from irrigated grounds. Tacna has one small 

 stream, conducted through the town by a paved channel, and it 



