also met a few date-palms with bifurcating stem, like that of the dum-palm, a plant also represented in the flora of South Tripolitana. The finest dates are said to be those yielded by the plantations of Gharia, in the upland valley of the Wady Zemzem, although these are still inferior to those of the Suf district in Algeria and of the Wady Draa in the south of Marocco. The number of dates cultivated whole of Tripolitana may be estimated at about two millions. Whether in the oases of the Jebel-es-Soda or of the Red Hamâda, or on the steppes skirting the Mediterranean seaboard, the plantations are everywhere formed of trees set close together, the groves thus producing at a distance the effect of verdant islands.
The requirements of irrigation and of the fertilisation of the female plant by the male pollen, in many places also the necessity of common defence against the attacks of marauding tribes, have caused all the dates of each district to be grouped in a compact mass. After leaving certain groves containing a hundred thousand plants in the closest proximity, the traveller does not again meet with a solitary specimen during a march of several hours, or even for days together. During the expedition of the brothers Beechey, a single palm was visible on the coast of the Great Syrtis near Cape Misrata, and when Barth visited the same district fifteen years afterwards, the tree had disappeared.
