Henna is a flowering plant also known as Lawsonia inermis. The leaves of the plant contain a natural dye that is released when the leaves are crushed.
Initially the dye color will range from an orange to red stain. The initial stain progresses into a deep brown stain within 2-3 days of henna paste removal.
Henna powder is a byproduct after the process of harvesting, drying, and finally crushing the leaves into a fine powder and then sifting for easy use.
Natural henna paste is created through a process of mixing finely sifted henna powder into a range of natural ingredients to help create a beautifully smooth paste. The reason that I mention the paste can contain a range of ingredients additional to henna powder is because every henna artist that makes their own henna paste will have their own special recipe.