The oasis of Laghouat is situated on the Oued Mzi, the upper portion
of the Oued Djedi, one of the most important oueds of Algeria. The
Oued Djedi runs in an easterly direction from Laghouat, receiving
many tributary oueds _en route_, by a rather long course to the
great Chott Melrirh, which is southeast of Biskra. Like other desert
rivers, the Oued Djedi is dry most of the year, but is occasionally
filled to overflowing with a rushing flood, which is of great erosive
power and may be very dangerous to the traveler. Above the town of
Laghouat, where the Oued breaks through the last pass of the Atlas,
the flood-plain is narrow, but upon leaving the pass the plain
widens until in the immediate proximity of the town it is about 1.5
kilometers in width. On either side of the flood-plain stretches the
arid plain (hamada), usually stony, but near the mountains covered
with low, slowly moving sand ridges. To the south of the oasis,
the arid plain merges into the topography characteristic of the
region of the dayas.
The portion of the oasis devoted to the cultivation of date and
other trees, and to gardens, is about 3 square kilometers in size,
but arable land extends above and below the town, so that outside of
the oasis, as delimited above, there are about 6 square kilometers,
all of which have at times been under cultivation. The last referred
to is the flood-plain of the oued and is used mainly for growing
barley. By the edge of the oued, or along the irrigating ditches,
are several characteristic species of plants, which may point to the
character of the primitive flora; for example, willows, oleander,
and _Tamarix_, with a few palms. The betoum (_Pistacia atlantica_),
which must surely have been an inhabitant of the oasis formerly,
is now apparently wholly absent. The species just mentioned are to
be found between the town and the pass above; but below the oasis,
owing to an apparently poorer water-supply, there are fewer large
species. Among those found are a few specimens of _Rhus oxyacantha_
and _Zizyphus vulgaris_, and it was probably below the town that
the betoum was to be found in earlier times.
The oasis is under intensive cultivation (see fig. 1). There are
about 300 gardens, each bounded by mud walls, and often separated
by picturesque, meandering lanes. The plant life, almost wholly
introduced, is luxuriant. In some gardens the effect is tropical,
where vines reach from tree to tree, making a canopy nearly sun-proof
and separating the spreading tops of the palms from the wealth of
shrubbery and herbaceous plants beneath. First among the trees of
the gardens, in numbers as well as in economic importance, is the
date palm, of which there are said to be about 30,000. Although
this is small in comparison to the number of date palms at Ouargla,
Touggourt, or the Oued Rirh, the dates are of great importance to
the dwellers at Laghouat, where the products of the gardens are
almost all consumed. The living tree provides shelter against the
intense heat and light of the desert, and the dead leaves constitute
an important source of fuel in a land where fuel is extremely
hard to obtain. The flesh of the date fruit is eaten by the Arab
and the cracked seeds are given to the camels. Without the date
a continuous occupancy of a remote oasis by the Arab is clearly
impossible. Besides the date palm fruit trees of other kinds are
abundant, among them the apricot, fig, mulberry, peach, pear, and
orange. The pomegranate and the table grape are also very generally
grown. The lowest story of the vegetation of the gardens is composed
of garden vegetables, such as artichoke, bean, carrot, melon,
pea, potato, squash, and radish. Among the ornamentals one sees
roses, asters, and chrysanthemums, and occasionally very luxuriant
cannas. One or two parks contain interesting introduced trees and
shrubs. We recognized among the trees _Ailanthus_, _Eucalyptus_,
umbrella, plane, poplar, pine, cypress, ash, locust, willow, and
St. John’s tree. The Barbary fig (_Opuntia ficus indica_) is also
common, but does not stray away from the best-watered situations.