Lawsonia inermis

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. Medicinal properties for the cure of renal lithiases, jaundice, wound healing; prevent skin inflammation. The bark is traditionally used in treatment of jaundice and enlargement of the spleen, renal calculus, leprosy and obstinate skin diseases. The species is named after the Scottish physician Isaac Lawson, a good friend of Linnaeus.
Description.
Henna is a tall shrub or small tree, standing . It is glabrous and multi-branched, with spine-tipped branchlets. The leaves grow opposite each other on the stem. They are glabrous, sub-sessile, elliptical, and lanceolate (long and wider in the middle; average dimensions are 1.5–5.0 cm x 0.5–2 cm or 0.6–2 in x 0.2–0.8 in), acuminate (tapering to a long point), and have depressed veins on the dorsal surface. Henna flowers have four sepals and a calyx tube, with spread lobes. Its petals are ovate, with white or red stamens found in pairs on the rim of the calyx tube. The ovary is four-celled, long, and erect. Henna fruits are small, brownish capsules, in diameter, with 32–49 seeds per fruit, and open irregularly into four splits.
Cultivation.
The henna plant is native to northern Africa, Asia and northern Australia, in semi-arid zones and tropical areas. It produces the most dye when grown in temperatures between . During the onset of precipitation intervals, the plant grows rapidly, putting out new shoots. Growth subsequently slows. The leaves gradually yellow and fall during prolonged dry or cool intervals. It does not thrive where minimum temperatures are below . Temperatures below will kill the henna plant.