179 
( 3 ) 
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 will 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 , Amarantaceae and Chenopodiaceae, re¬ 
minded 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 
mountain. 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 
