Henna facts

• The English name "henna" comes from the Arabic حِنَّاء, pronounced colloquially ħinna.
• Henna is a flowering plant used since antiquity to dye skin, hair, fingernails, leather and wool.
• Henna flowers have four sepals and a 2 mm calyx tube with 3 mm spread lobes. Petals are obvate, white or red stamens inserted in pairs on the rim of the calyx tube.
• Henna's coloring properties are due to lawsone, a burgundy organic compound that has an affinity for bonding with protein.
• The name is also used for dye preparations derived from the plant, and for the art of temporary tattooing based on those dyes.
  Henna is commercially cultivated in western India, Bangladesh, Pakistan, Morocco, Yemen, Iran, Afghanistan, Somalia, Sudan, Tunisia, Libya, Saudi Arabia and Egypt.
• The henna plant is native to tropical and subtropical regions of Africa, southern Asia, and northern Australasia in semi-arid zones. 
• Use of henna for body art has enjoyed a recent renaissance due to improvements in cultivation, processing, and the emigration of people from traditional henna-using regions.
• Henna has been used since the Bronze Age to dye skin (including body art), hair, fingernails, leather, silk and wool.
• Henna was listed in the medical texts of the Ebers Papyrus (16th c BCE Egypt) and by Ibn Qayyim al-Jawziyya (14th c CE (Syria and Egypt) as a medicinal herb.
• For skin dyeing, a paste of ground henna (either prepared from a dried powder or from fresh ground leaves) is placed in contact with the skin from a few hours to overnight. Henna stains can last a few days to a month depending on the quality of the paste, individual skin type, and how long the paste is allowed to stay on the skin.
• Henna repels some insect pests and mildew.
• Henna also acts as an anti-fungal and a preservative for leather and cloth.
• Henna flowers have been used to create perfume since ancient times, and henna perfume is experiencing a resurgence.