Neem
(Azadirachta indica) trunk in Kolkata W IMG 6190.jpg|100px|thumb| trunk in   , ]
'Neem (Azadirachta indica, Melia azadirachta L., Antelaea azadirachta (L.) Adelb.) is a ), DogonYaro (Margosa, Neeb (), Nimtree, Nimba (Vepu, Vempu, Vepa (), Bevu in language|Kannada], Veppam in (language|Tamil]),arya veppu in malayalam and Indian-lilac. In East Africa it is also known as Mwarobaini ([ which means the tree of the 40; it's said to treat 40 different diseases.
Neem is a fast-growing [ that can reach a height of 15-20 m, rarely to 35-40 m. It is [ but under 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.
The trunk is relatively short, straight and may reach a diameter of 1.2 m. The bark is hard, fissured or scaly, and whitish-grey to reddish-brown. The sapwood is greyish-white and the heartwood reddish when first exposed to the air becoming reddish-brown after exposure. The root system consists of a strong taproot and well developed lateral roots.
The alternate, leaves are 20-40 cm long, with 20-31 medium to dark green leaflets about 3-8 cm long. The terminal leaflet is often missing. The s 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.
(Azadirachta indica) leaves & flowers in Kolkata W IMG 6199.jpg|left|thumb| leaves & flowers in  , ]The [ (white and fragrant) are arranged axillary, normally more-or-less drooping [ which are up to 25 cm long. The [ which branch up to the third degree, bear 150-250 flowers. An individual flower is 5-6 mm long and 8-11 mm wide. [ bisexual flowers and male flowers exist on the same individual (polygamous).
The [ is a glabrous olive-like [ 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 [ (kernels) having a brown seed coat.
Commercial plantations of the trees are not considered profitable. Around 50,000 neem trees have been planted near to provide shelter for the [ Ganguli (2002) [ Neem: A therapeutic for all seasons, Current Science, Vol. 82, No. 11, June. pp. 1304
The neem tree is very similar in appearance to the [ all parts of which are extremely poisonous.

# Ecology
(Azadirachta indica) tree with flowers in Kolkata W IMG 6189.jpg|100px|thumb|left|tree with flowers in  , ]The neem is a tree noted for its drought resistance. Normally it thrives in areas with sub-arid to sub-humid conditions, with an annual rainfall between 400 and 1200 mm. It can grow in regions with an annual rainfall below 400 mm, but in such cases it depends largely on the ground water levels. Neem can grow in many different types of [ but it thrives best on well drained deep and sandy soils (pH 6.2-7.0). It is a typical tropical/subtropical tree and exists at annual mean temperatures between 21-32 AC. It can tolerate high to very high temperatures. It does not tolerate temperature below 4 AC (leaf shedding and death may ensue).
Neem is a life giving tree in South India, especially for the dry coastal southern districts. It is one of the very few shade giving trees that thrive in the drought prone areas. The trees are not at all delicate about the water quality and thrive on the merest trickle of water, whatever the quality be. In Tamil Nadu it is very common to see neem trees used as shade giving trees lining the streets or in most people's back yards. In very dry areas like Sivakasi, the trees are planted in large tracts of land, in whose shade fire works factories (that are banned from using electricity for lighting) function.

# Chemical compounds
The active principles of the plant were brought to the attention of products] in , while working at the Scientific and Industrial Research Laboratory at University], for the first time extracted three bitter compounds from oil], which he provisionally named as nimbin, nimbinin, and nimbidin respectively.

# Usage
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In India, the tree is variously known as "Divine Tree", "Heal All", "Nature's Drugstore", "Village Pharmacy" and "Panacea for all diseases".  Products made from neem have proven medicinal properties, being anthelmintic, antifungal, antidiabetic, antibacterial, antiviral, anti-infertility, and sedative.  It is considered a major component in medicine] and is particularly prescribed for skin disease.
- Neem twigs are used for brushing teeth in India, Bangladesh and Pakistan. This practice is perhaps one of the earliest and most effective forms of dental care.
- All parts of the tree (seeds, leaves, flowers and bark) are used for preparing many different medical preparations.
- oil] is used for preparing cosmetics (soap, shampoo, balms and creams), and is useful for skin care such as acne, and keeping skin elasticity.
- Besides its use in traditional Indian medicine the neem tree is of great importance for its anti-desertification properties and possibly as a good carbon dioxide sink.
- Practictioners of traditional Indian medicine recommend that patients suffering from Chicken Pox sleep on neem leaves.
- Gum] is used as a bulking agent and for the preparation of special purpose food (those for diabetics).

## Horticultural usages
Neem is a source of environment-friendly Among the isolated , [ (such as [ are effective in insect growth-regulating activity. The unique feature of neem products is that they do not directly kill the pests, but alter the life-processing behavior in such a manner that the insect can no longer feed, breed or undergo metamorphosis.
The oil is also used in sprays against [ in [ and [
The tender shoots and flowers of the neem tree are eaten as a in India. Neem flowers are very popular for their use in  which is made on Ugadi day in South India. A soup like dish called Veppampoo Rasam (translated as 'juice of neem flower') made of the flower of neem is prepared in .
Neem is also used in parts of mainland Asia], particularly in and  is a rich source of protein.