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336
NOTES OF A BOTANIST
luxuriance, their ample fronds never mutilated as they are wont to be
by
in other regions. On the
caterpillars
river-bank
grow also fine old Willows (Sa/ix Hiunboldtiana\ noticeable for
their slender branches and long, narrow, yellow -green
contrasting strongly
leaves,
with the dark green of the spreading Guavas
(Ingje sp.), and with the bright green foliage (passing to rose at
the tips of the branches) of the Mango (Mangifera indica).
Mingled with these, or in square openings in the Algarrobo
woods, are cultivated patches of sweet potatoes, yucas, maize, and
cotton plants, the latter distinguishable by their pale but fresh
green colour. It was a magnificent sight to look from this cliff
towards the mouth of the Chira when the sun was just setting
over it, steeping the hills of Mancora in purple and violet, and
gilding the fronds of the palms and the salient edges of the
adjacent cliffs, while the deep recesses of the latter and the
Algarrobo woods were already shrouded in gloom.
On descending into the valley, the natural forest of Algarrobo
is found to occupy a strip of from a few hundred yards to three
or four miles in width, extending from the river on each side as
far out as there is permanent moisture at a moderate depth. It
is divided by fences into plots of various sizes, all private
property, except a small breadth of common lands adjacent to
each village. I was surprised to hear these plots called not
"woods "but " pastures "
(potreros), for the trees grow in them
as thickly as trees do anywhere, and there is not underneath
them an herb of any kind. They
are so called because the fruit
of the is Algarrobo the main article of food for most of the
domesticated animals, and therefore corresponds to the pasturage
of other countries. The Algarrobo is a prickly tree, rarely exceeding
40 feet in height, with rugged bark not unlike that of the
elm, but more tortuous, and with bipinnate foliage like that
of the Acacias, to which it is closely allied. The roots penetrate
the soil to only a slight depth, but extend a very long way
horizontally. On the desert I have seen an Algarrobo root,
no thicker than the finger, stretch away to a length of 40 yards,
evidently in quest of moisture. As the trunks never grow
straight, and soon become tolerably corpulent, and their roots
take too little hold of the friable earth to sustain them against
the squally winds, they very generally fall over in age either into
a reclining posture or quite prostrate, but immediately begin to
turn their heads upwards, send off new roots from every part of
the trunk in contact with the soil, and thus get up anew in the
world : so that an old potrero or Algarrobo wood has a most
irregular and fantastic appearance. Twice in the year the
Algarrobo puts forth numerous pendulous racemes of minute
yellow-green flowers, which nourish multitudes of small flies and
beetles, that in their turn afford food to flocks of birds most of