Easton's Bible Dictionary (1897)
(Heb. copher), mentioned in Cant. , “henna”), is the al-henna of the Arabs, a native of Egypt, producing clusters of small white and yellow odoriferous flowers, whence is made the Oleum Cyprineum. From its leaves is made the peculiar auburn dye with which Eastern women stain their nails and the palms of their hands. It is found only at Engedi, on the shore of the Dead Sea. It is known to botanists by the name Lawsonia alba or inermis, a kind of privet, which grows 6 or 8 feet high.
The margin of the Authorized Version of the passages above referred to has “or cypress,” not with reference to the conifer so called, but to the circumstance that one of the most highly appreciated species of this plant grew in the island of Cyprus.
Smith's Bible Dictionary (1863)
There can be no doubt that “camphire” is the Lawsonia alba of botanists, the henna of Arabian naturalists. The henna plant grows in Egypt, Syria, Arabia and northern India. The flowers are white and grow in clusters, and are very fragrant.