Azadirachta indica, commonly known as neem, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of two species in the genus Azadirachta, and is native to the Indian subcontinent. It is typically grown in tropical and semi-tropical regions. Neem trees also grow on islands in southern Iran. Its fruits and seeds are the source of neem oil. Description Neem is a fast-growing tree that can reach a height of , and rarely . It is evergreen, shedding many of its leaves during the dry winter months. The branches are wide and spreading. The fairly dense crown is roundish and may reach a diameter of . The neem tree is similar in appearance to its relative, the chinaberry (Melia azedarach). The opposite, pinnate leaves are long, with 20 to 30 medium to dark green leaflets about long. The terminal leaflet often is missing. The petioles are short. White and fragrant flowers are arranged in more-or-less drooping axillary panicles which are up to long. The inflorescences, which branch up to the third degree, bear from 250 to 300 flowers. An individual flower is long and wide. Protandrous, bisexual flowers and male flowers exist on the same individual tree. The fruit is a smooth (glabrous), olive-like drupe which varies in shape from elongate oval to nearly roundish, and when ripe is by . The fruit skin (exocarp) is thin and the bitter-sweet pulp (mesocarp) is yellowish-white and very fibrous. The mesocarp is thick. The white, hard inner shell (endocarp) of the fruit encloses one, rarely two, or three, elongated seeds (kernels) having a brown seed coat. The neem tree is often confused with a similar looking tree called bakain. Bakain also has toothed leaflets and similar looking fruit. One difference is that neem leaves are pinnate but bakain leaves are twice- and thrice-pinnate. Etymology Neem (नीम/نیم) is a Hindustani noun derived from Sanskrit Nimba (निंब). Ecology The neem tree is noted for its drought resistance. Normally it thrives in areas with sub-arid to sub-humid conditions, with an annual rainfall of . It can grow in regions with an annual rainfall below 400 mm, but in such cases it depends largely on ground water levels. Neem can grow in many different types of soil, but it thrives best on well drained deep and sandy soils. It is a typical tropical to subtropical tree and exists at annual mean