Balm of Gilead here is Commiphora gileadensis, the Arabian balsam tree, a shrub or small tree of the Burseraceae family found in Saudi Arabia, Yemen, southern Oman and Sudan, and in south-eastern Egypt, where it may have been introduced; Grieve gives its home as the lands on both sides of the Red Sea. It grows up to about four metres, is rarely spiny, and has bark that peels or flakes when cut, leaves of three to five small leaflets, red flowers and dull red fruit striped lengthwise with white, while a snapped twig or crushed leaf gives off a pleasant scent. Cuts in the bark release a sap that soon hardens into a sweet-smelling gum, which is chewed and burned as incense. In antiquity the tree was prized for a costly perfume thought to come from it and for the healing virtues credited to its sap, wood, bark and seeds. Grieve, writing in 1931, relays Josephus on the Queen of Sheba bringing it to Solomon and its cultivation on Mount Gilead giving it its name, and Pliny on its arrival in Rome with the generals of Vespasian; she records that the juice was called opobalsamum, the twigs xylobalsamum and the fruit carpobalsamum, and that it was grown in guarded gardens near Cairo. The name has wandered: firs and poplars have borne it too, and the Wikipedia article on the species says the true ancient balm appears to have come from the unrelated Pistacia lentiscus.