The olive indeed in all ages clothed the hills of a large part of the country; but the orange and lemon, are a late importation from the East, while the cactus or Indian fig and the aloe, both of them so conspicuous on the shores of southern Italy, as well as of the Riviera of Genoa, are of Mexican origin, and consequently could not have been introduced earlier than the 16th century.
The pear, lemon, plum, fig and other trees likewise flourish.
Timber trees are almost confined to the river valleys, where willows, yellow wood, iron wood, red wood, mimosas and, in deep gorges, the wild fig are found.
Above the sea the fig is common.
Opuntia, the prickly pear, or Indian fig cactus, is a large typical group, comprising some 150 species, found in North America, the West Indies, and warmer parts of South America, extending as far as Chile.
This gives rise to the peculiar inflorescence of Dorstenia, or to that of the fig (fig.
The fig is a common door-yard tree as in other Gulf and South Atlantic states, and is never killed down by frost.
In the southern provinces flourish also various subtropical exotics, such as the banana, the West Indian cherimoya, and the prickly pear or Indian fig (Opuntia vulgaris), the last frequently grown as a hedge-plant, as in other Mediterranean countries, and extending even to the southern part of the table-land.
Among the larger trees are the mountain cedar, reaching to 100 ft.; the gob, which bears edible berries in appearance something like the cherry with the taste of an apple, grows to some 80 ft., and is found fringing the river beds; the hassadan, a kind of euphorbia, attaining a height of about 70 ft.; and the darei, a fig tree.
Among fruit trees the vine, apricot, peach, apple, quince, fig and banana are cultivated in the highlands, and in the lower country the date palm flourishes, particularly throughout the central zone of Arabia, in Hejaz, Nejd and El Hasa, where it is the prime article of food.