ON THE PACIFIC COAST 335 
I have never seen either leaves or flowers of the Yuca del 
monte ; but, from the description given me of it, I should suppose 
it a Convolvulacea, allied to the sweet potatoes (Batatas), and the 
lanceolate leaves point to the genus Aniseia. 
The arborescent vegetation of the desert, although perhaps 
really more scanty than the herbaceous, is from its nature more 
conspicuous wherever it exists. There are points from which not 
a single tree is visible all around the horizon, but they are rare ; 
generally the view takes in a few widely-scattered trees growing 
in basin-shaped hollows or towards the base of slopes, where at 
a certain depth there is permanent moisture throughout the wide 
interval between the anos de aguas, at which epochs the supply 
is renewed. Wells dug in such sites reach water (too brackish 
for drinking) at various depths, the first deposit often at only 
a few feet from the surface. The moisture derived from the 
garuas, scanty as it is, no doubt aids in keeping the desert plants 
alive ; and we have already seen that the air is never so ex- 
cessively dry as might be supposed, but, on the contrary, some- 
times approaches complete saturation. The trees of the desert 
are the Algarrobo {Frosopis horrida\ the Vichaya {Cappaj'is 
crotonoides\ the Zapote del perro i^Colicode?idrum scabriduin'}\ 
and an Apocynea with numerous slender branches, bright green 
lanceolate acuminate leaves, axillary clusters of small w^hite 
flowers, and fruits, consisting of small twin drupaceous follicles, 
which are slender, curved, and coated with a thin white flesh. 
The Capparis and the Apocynea, although they grow to be trees 
in favourable situations, as in valleys near the sea, are mere 
shrubs on the desert ; and the Prosopis and Colicodendron are 
low trees of very scraggy growth, their branches all bent one 
way by the prevailing wind, and the trunk itself often semi- 
prostrate. 
Far away over the desert a tall branched Cactus begins to be 
met with; the same species abounds on the desert -coast of 
, Ecuador. Farther still, near the roots of the Cordillera, the 
vegetation becomes gradually more dense and varied, comprising 
several other kinds of trees, and amongst them most of those 
about to be mentioned as denizens of the valleys. 
When the traveller across the despoblado comes suddenly on 
one of the valleys, he passes at once from a desert to a garden, 
whose charms are enhanced by their unexpectedness. Standing 
on the cliff that overlooks the Chira, about Amotape, he sees at 
his feet a broad valley filled with perpetual verdure, the great 
mass of which is composed of the pale green foliage of the 
Algarrobo ; but the course of the river that winds through it is 
marked (even where the river itself is not seen) by lines or 
groups of tall Coco palms, here and there diversified by the more 
rigid Date palm, both growing and fruiting in the greatest 
