What is the source of the dye henna used to dye skin, hair and fingernails

Lawsonia inermis, also known as hina, the henna tree, the mignonette tree, and the Egyptian privet, is a flowering plant and the sole species of the genus Lawsonia. It is the source of the dye henna used to dye skin, hair and fingernails, as well as fabrics including silk, wool and leather. The henna plant is native to northern Africa, western and southern Asia, and northern Australia, in semi-arid zones and tropical areas.