“Northern Africa is especially characterized by the extreme rarity of rains, the dryness of the atmosphere, and the extremes of temperature; the absence of great ranges of mountains and of permanent water-courses gives an aspect quite special to the desert-like vegetation. The number of species growing spontaneously does not exceed 500. The greater number of these are perennials, which grow in tufts, and have a dry and sterile aspect, giving them a characteristically rugged and hard appearance. The families represented in the Algerian Sahara in greatest number are _Compositæ_, _Graminaceæ_, _Leguminosæ_, _Cruciferæ_, and _Chenopodiaceæ_. Among the ligneous species are Tamarisks, a genus of elegant flowering shrubs, and the _Pistacia atlantica_. The date-tree is, however, the chief source of wealth in the gardens of the oases. This tree is cultivated, not alone for the abundance and variety of its products, but also for its shade, which secures other cultivated plants from the violence of the winds, and maintains in the soil the moisture required for the cultivation of other crops. “Besides the date, an oasis generally presents an abundant crop of figs, pomegranates, apricots, frequently the vine. The peach, the quince, the pear, and the apple, are planted in gardens, and in the oases, the citron, the orange-tree, olives, barley, more rarely still, wheat, are cultivated in the irrigated lands of the neighborhood, and in the intervals between the date plantations. Onions, beans, carrots, turnips, and cabbages, occupy a large place among the plants cultivated. Pimento is also largely cultivated for the stimulating properties of its fruit, which render it a favorite condiment with the Arabs. The egg-plant and the tomato are cultivated in some gardens for their fruit. Numberless species of _Cucurbitaceæ_ are also sown in the gardens in summer, and sometimes attain a great size. The gombo (_Hibiscus esculentus_) is cultivated here and there by the negroes for its mucilaginous fruit. The industrial and fodder plants are principally hemp, represented by a dwarf variety (Haschich), which is not employed as a textile plant, but its extremities are smoked by some of the less fervent Mussulmans. Tobacco is also cultivated. Henna (_Lawsonia inermis_), the leaves of which have been employed in dyeing a black color, scarcely exists except in the oasis of Ziban.”