Azadirachta indica (Neem) is a tree in the mahogany family Meliaceae. It is one of two species in the genus Azadirachta, and is native to India, Burma, Bangladesh, Sri Lanka, Malaysia and Pakistan, growing in tropical and semi-tropical regions. Other vernacular names include Neem (Hindi, Urdu), Nim ((Bengali)), Nimm (Punjabi), Arya Veppu (Malayalam), Azad Dirakht (Persian), Nimba (Sanskrit, Oriya), Kadu-Limba (Marathi), DogonYaro (in some Nigerian languages), Margosa, Neeb (Arabic), Nimtree, Vepu, Vempu, Vepa (Telugu), Bevu (Kannada), Kohomba (Sinhala), Vembu (Tamil), Tamar (Burmese), sầu đâu, xoan Ấn Độ (Vietnamese), Paraiso (Spanish), and Indian Lilac (English). In East Africa it is also known as Muarubaini (Swahili), which means the tree of the 40, as it is said to treat 40 different diseases.
Neem is a fast-growing tree that can reach a height of 15–20 m (about 50–65 feet), rarely to 35–40 m (115–131 feet). It is evergreen, but in severe drought it may shed most or nearly all of its leaves. The branches are wide spread. The fairly dense crown is roundish or oval and may reach the diameter of 15–20 m in old, free-standing specimens.
Trunk
The trunk is relatively short, straight and may reach a diameter of 1.2 m (about 4 feet).It is classified as a bush but it is not very weak.
Leaves
The opposite, pinnate leaves are 20–40 cm (8 to 16 in.) long, with 20 to 31 medium to dark green leaflets about 3–8 cm (1 to 3 in.) long. The terminal leaflet is often missing. The petioles are short. Very young leaves are reddish to purplish in colour. The shape of mature leaflets is more or less asymmetric and their margins are dentate with the exception of the base of their basiscopal half, which is normally very strongly reduced and cuneate or wedge-shaped.
Flowers
The (white and fragrant) flowers are arranged axillary, normally in more-or-less drooping panicles which are up to 25 cm (10 in.) long. The inflorescences, which branch up to the third degree, bear from 150 to 250 flowers. An individual flower is 5–6 mm long and 8–11 mm wide. Protandrous, bisexual flowers and male flowers exist on the same individual.
Fruit
The fruit is a smooth (glabrous) olive-like drupe which varies in shape from elongate oval to nearly roundish, and when ripe are 1.4-2.8 x 1.0-1.5 cm. The fruit skin (exocarp) is thin and the bitter-sweet pulp (mesocarp) is yellowish-white and very fibrous. The mesocarp is 0.3-0.5 cm 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 very similar in appearance to the Chinaberry, all parts of which are extremely poisonous.